Journal of the History of Biology, Vol. 4, No. 1

Journalof the Historyof Biology SPRING 1971: VOLUME 4, NUMBER 1

THE BELKNAPPRESS OF HARVARD UNIVERSITY PRESS

Editor: EverettMendelsohn,HarvardUniversity Assistant Editor: Judith P. Swazey, Harvard University ? Copyright 1971 by the President and Fellows of Harvard College

CONTENTS Conflict of Concepts in Early Vitamin Studies

I

AARON J. IHDE AND STANLEY L. BECKER

The Background to Eduard Buchner's Discovery of Cell-Free Fermentation

35

ROBERT KOHLER

Organismic and Holistic Concepts in the Thought of L. J. Henderson

63

JOHN PARASCANDOLA

Notes on SourceMaterials:The L. J. HendersonPapers at Harvard

115

JOHN PARASCANDOLA

Schr6dinger'sProblem:What Is Life?

119

ROBERT OLBY

An UnacknowledgedFoundingof MolecularBiology: H. J. Muller'sContributionsto Gene Theory,1910-1936

149

ELOF AXEL CARLSON

ESSAY REVIEW: -Haldane and Huxley: The First Appraisals

171

PAUL GARY WERSKEY

USSR: Current Activities in the History of Physiology

and Psychology

185

JOSEF BROItEK

Darwin, Malthus, and Selection

209

SANDRA HERBERT

The J. H. B. Bookshelf

219

JOURNALOF THE HISTORYOF BIOLOGYis published semiannually in the spring and autumn by the Belknap Press of Harvard University Press, 79 Garden Street, Cambridge, Massachusetts, 02138. Editorial Board: Bentley Glass, State University of New York, Stony Brook; Hebbel E. Hoff, M.D., Baylor University; Ernst Mayr, Harvard University; Everett Mendelsohn, Harvard University; Jane Oppenheimer, Bryn Mawr College. Advisory Editorial Committee: Enrique Beltr6n, Mexico; Georges Canguilhem, France; John T. Edsall, M.D., U.S.A.; A. E. Gaissinovitch, U.S.S.R.; Ralph W. Gerard,M. D., U.S.A.; John C. Greene, U.S.A.; Marc Klein, M.D., France; Vladislav Kruta, M.D., Czechoslovakia; Joseph Needham, England; Dickinson W. Richards, M.D., U.S.A.; K E. Rothschuh, M.D., Germany; Conway Zirkle, U.S.A. Editorial Correspondence and manuscripts should be sent to Professor Everett Mendelsohn, Editor, Journal of the History of Biology, Holyoke Center 838, Cambridge, Massachusetts, 02138. Subscription correspondence should be addressed to Mrs. W. H. Carpenter, Harvard University Press, 79 Garden Street, Cambridge, Massachusetts, 02138.

Subscriptions, which are payable in advance, will start with the first issue published after receipt of the order. Please make remittances payable to Harvard University Press. Subscription rates are $7.50 a year In the U.S.; $8.50 in all other countries; $4.50 for a single copy. Joural Design by David Ford

Conflictof Conceptsin EarlyVitaminStudies AARON J. IHDE and STANLEY L. BECKER University of Wisconsin, Madison, Wisconsin

The concept that foods must contain organic trace nutrients in addition to adequate amounts of fats, carbohydrates, proteins, and minerals was clearly enunciated in 1912 and became firmly established as part of a continuing tradition during the next decade. The notion that traces of specific organic materials are necessary for satisfactory nutrition had been put forth many times in the past, and in some cases, quite convincingly. But these tentative hypotheses generally failed to make a lasting impression on public health personnel, and they failed to dislodge the belief, widely held in the last half of the nineteenth century, that the gross constituents of foods, carbohydrates, fats, proteins, and minerals would provide adequate nourishment for man and farm animals. As a consequence of studies at the Lister Institute, where he had been isolating fractions of rice polishings and yeast which were curative of polyneuritis in birds, Casimir Funk suggested in 1912, It is now known that all these diseases [beriberi, scurvy, rickets, pellagra] . . . can be prevented and cured by the addition of certain preventive substances; the deficient substances which are of the nature of organic bases, we will call "vitamines"; and we will speak of a beri-beri or scurvy vitamine, which means a substance preventing the specific disease.' The same year also saw the introduction of the term "accessory food factors" by F. Gowland Hopkins,2 of Cambridge University. However, Hopkins had already alluded to the need for 1. C. Funk, "The Etiology of Deficiency Disease," J. State Med., 20 (1912), 341-365. Regarding Funk's life and work, see B. Harrow, Casimir

Funk, Pioneer in Vitamins and Hormones (New York, 1955).

2. F. G. Hopkins, 'Feeding Experiments Illustrating the Importance of Accessory Factors in Normal Dietaries," J. Physiol., 44 (1912), 425-460. Journal of the History of Biology, vol. 4, no. 1 (Spring 1971), pp. 1-33.

1

AARON J. IMDE AND STANLEY L. BECKER

trace nutrients in a speech in 1906, where he describedexperiments in which animals were fed the maize protein, zein, together with fats, carbohydratesand salts; but growth was unsatisfactory even when the amino acid tryptophan, which is lacking in zein, was addedto the diet. Hopkinsremarked, . . .no animal can live upon a mixture of pure protein, fat, and carbohydrate,and even when the necessary inorganic material is carefully supplied the animal still cannot flourish. The animal body is adjusted to live either upon plant tissues of the tissues of other animals, and these contain countless substances other than the proteins, carbohydrates,and fats. Physiological evolution, I believe, has made some of these well-nigh as essential as are the basal constituents of diet . . . The field is almost unexplored; only is it certain that there are many minor factors in all diets of which the body takes account. In diseases such as rickets, and particularly in scurvy, we have had for long years knowledge of a dietetic factor; but though we know how to benefit these conditions empirically, the real errors in the diet are to this day quite obscure. They are, however, certainly of the kind which comprses these minimal qualitativefactors that I am considering. Scurvy and rickets are conditions so severe that they force themselvesupon our attention;but many other nutritiveerrors affect the health of individuals to a degree most importantto themselves, and some of them depend upon unsuspected dietetic factors. I can do no more than hint at these matters,but I can assert that later developments of the science of dietetics will deal with factors highly complex and at present unknown.8 A year earlier, C. A. Pekelharinghad told the Dutch Society for the Advancementof Medicine, It is impossible to keep an anal alive by feeding it protein, fats, carbohydrate,necessary salts and water . . . It is for nutrition of the greatest importance to know what substance it is which one needs besides protein, fat, and carbohydrate . . . When white mice are fed with bread baked

from casein, albumin, rice flour, bran, and a mixture of all 3. F. G. Hopkins, "The Analyst and the Medical Man," Analyst, 31 (1906), 385-397. This address is reprinted along with the Nobel Prize Address, "The Earlier History of Vitamin Research," and several others in J. Needham and E. Baldwin, Hopkins and Biochemistry (Cambridge, Eng., 1949). This volume also contains

Hopkins by three of his associates.

2

an autobiography

and evaluations

of

Conflict of Concepts in Early Vitamin Studies salts which should be present in food, they die of deficiency if they are given water alone to drink . . . If in place of water, they are given milk to drink, they remain healthy, although the quantity of protein, milk sugar and fat with the milk is extremely insignificant.4 More than four years after the pronouncements of Funk and Hopkins, E. V. McCollum and Cornelia Kennedy, at the Wisconsin Agricultural Experiment Station, introduced the terms "fat-soluble A" and "water-soluble B" for unknown factors which are present in milk and certain other foods and are essential for the growth and well-being of experimental animals.5 Although the organic trace nutrient concept did not become firmly established until the second decade of the twentieth century, there were numerous earlier evidences for the existence of such trace substances in foods. EVIDENCE OF FOOD DEFICIENCY DISEASES The food diseases singled out by Funk as probable deficiency diseases had had a long history and had each been associated with food as a causative factor. Scurvy in particular had been described by ancient medical writers and had been encountered during military campaigns, during sieges, in prisons, and aboard ship.6 Following the onset of the great navigations it became famous as the scourge of the sea. Beriberi was an old Oriental disease which flared up in various parts of the East, particularly late in the nineteenth century when European colonial interests were being developed.7 Rickets was most frequently associated with children and restricted mostly to northern lands.8 Pellagra had an entirely modern history and proved 4. C. A. Pekelharing, "About our Knowledge of the Value of Foods from Chemical Factories," Ned. Tijdschr. Geneesk, 41 (1905), 111-124. For an English translation see S. L. Becker, "The Emergence of a Trace Nutrient Concept through Animal Feeding Studies," Ph.D. thesis, University of Wisconsin, Madison, 1968, pp. 301-322. 5. E. V. McCollum, and Cornelia Kennedy, "The Dietary Factors Operating in the Production of Polyneuritis," J. Biol. Chem., 24 (1916), 491-502. 6. A. J. Lorenz, "The Conquest of Scurvy," J. Am. Dietetic Assoc., 30 (1954), 665-670; H. J. van Wersch, Scurvy as a Skeletal Disease (Utrecht, 1954), pp. 5-28; E. V. McCollum, A History of Nutrition (Boston, 1957), and Present (Philadelphia, 1920). pp. 252-265; A. Hess, Scurvy-Past 7. E. B. Vedder, Beriberi, (New York, 1913), pp. 1-10; R. R. Williams, Toward the Conquest of Beriberi, (Cambridge, Mass., 1961), pp. 3-35. 8. A. Hess, Rickets, Including Osteomalacia and Tetany (Philadelphia, 1927), pp. 22-37. McCollum, fn. 6 above, pp. 266-290.

3

AARON J. MIDEAND STANLEY L. BECKER

to be endemic in those parts of the world where corn (maize) was an importantcomponentof the diet.9 Almost four centuries before the pronouncementsof Funk, Hopkins, and Pekelharing,scurvy and its cure were clearly described. When Jacques Cartier had three ships immobilizedin the ice in the St. LawrenceRiver during the winter of 1535-36 his crews were severely stricken by the disease. Almost the whole crew was suffering from lassitude, swollen and blackened limbs, sore gums and loosening teeth, and hemorrhages. An autopsy performed on the first man who died revealed a white and shriveled heart, lungs black and gangrenous, and evidence of severe internal hemorrhages.From the local Indians Cartierlearned to prepare an infusion from the bark and leaves of a tree named Annedda in his journal. The stricken men drank the unpleasant brew and poured it on their legs. Recoveries were miraculously rapid.'0 It is presumed that the tree was the Canadianfir whose needles have been found to contain a substantialamountof ascorbicacid." Two centuries later the Scottish ship surgeon James Lind persuasively demonstratedthat scurvy can be cured by administration of the juice of fresh oranges and lemons. In 1746, aboard the Salisbury, he treated six pairs of scorbutic sailors with standard remedies. Two sailors treated with oranges and lemons showed rapid recovery. The ten receiving other remedies (cider, vinegar, seawater, sulfuric acid, or an antiscorbutic electuary) showed no improvement except possibly the two who received a quart of cider daily. In his book, A Treatise on the Scurvy,12 Lind not only describedhis experimentsbut presented a history of the disease which revealed the value of fresh fruits and vegetablesin its treatnent and prevention. When Captain James Cook embarkedon his second voyage of exploration in 1772 he heeded Lind's teachings by seeing that his crew was provided with fresh fruits and vegetables. During the three-year voyage only one crewman aboard the 9. S. R. Roberts, Pellagra (St. Louis, 1913), pp. 43-73; G. M. Niles, PeUagra, An American Problem, (Philadelphia, 1916), 2nd ed., pp. 11-24. 10. H. P. Biggar, "The Voyages of Jacques Cartier,"Publications of the Public Archives of Canada, no. 11, 1924. Also see von Wersch, fn. 6 above, p. 9. 11. A. Scheunert and J. Reschke, "Coniferennadeln und deren Absude als Vitamin C-triger," Klin. Wochenschr. 19 (1940), 976-979. 12. J. Lind, A Treatise on the Scurvy (Edinburgh, 1753, with enlarged

editions in 1757 and 1772). A reprint of the first edition was published under the editorship of C. P. Stewart and D. Guthrie, Lind's Treatise on Scurvy (Edinburgh, 1953). This reprint has some valuable supplementary essays on Lind, his contemporaries, and the subsequent history of scurvy.

4

Conflict of Concepts in Early Vitamin Studies Resolution was lost to scurvy,13 a striking contrast to the heavy losses customarily suffered on long sea voyages, or during prolonged sieges on land. Although Lind, who became Physicianin-Charge of the Haslar Naval Hospital at Portsmouth in 1758, campaigned for reform of the British naval diet, the Admiralty resisted his doctrines, and it was only in 1795, the year after Lind's death, that lemon juice became a required component of the sailor's diet. Because of problems associated with preservation and adulteration, the lemon juice failed to uniformly prevent scurvy and many medical officers lacked confidence in its use. Furthermore, the lime was looked upon as the equivalent of the lemon, and lime juice had official sanction for use in place of lemon juice. Lime juice, however, contains a lower level of ascorbic acid and is a less effective antiscorbutic agent. According to Hess, there is no archaeological evidence that rickets occurred in ancient Egypt or Greece but a small amount of such evidence suggests that the disease was known in northern Europe. Soranus of Ephesus and Galen referred to it in Rome in the second century after Christ but there are no further literary references until the sixteenth century when the disease was described by Theodosius of Bologna. In the next century there are several medical treatises describing the disease, that of Francis Glisson,14 in 1650 being a classic. The disease had become endemic among infants in western England thirty years earlier, and Glisson accurately described the enlarged heads of infants, the swollen wrists and ankles, the deformity of the chest, and the deformed abdomen characteristic of advanced cases, but he sought to understand the disease in terms of Galenical theory. Rickets became the subject of numerous dissertations in Britain, Germany, and France, indicative of the widespread occurrence of the disease, particularly in the larger cities. This pattern continued into the twentieth century, the disease becoming particularly troublesome in the large cities during World War I. Cod liver oil had been recommended as an antirachitic agent as early as 1789 by Darbey and, even earlier, it had extensive use among fishermen along the northern coasts of Europe. However, when the '"Dreckapotheke"of 13. J. Cook, "The Method Taken for Preserving the Health of the Crew of Her Majesty's Resolution on Her Voyage Around the World," a letter addressed to John Pringle from Capt. James Cook, Mar. 5, 1776, Phil. Trans. Royal Soc. London, 66 (1776), 402-406. Also see 3. C. Beaglehole, ed., The Journals of Captain James Cook on His Voyages of Exploration, 4 vols., (Cambridge, Eng., 1961), vol. II: The Voyage of the Resolution and Adventure, 1772-1775, pp. 14, 15, 111, 165-6, 187, 191, 954-6. 14. F. Glisson, De Rachitide sive Morbo Puerili, qui vulgo The Rickets dictitur (London, 1650); first English ed., 1651.

5

AARON J.

DE AND STANLEY L. BECKER

medieval medicine fell into discard during the medical enlightenment of the nineteenth century, the vile tasting cod liver oil went into disfavor in medical circles although it continued to have popularityas a folk remedy.15 Of the four diseases, beriberi was most clearly associated with a food inadequacyby 1900 as a consequence of studies in the Orient during the last two decades of the preceding century. Although the disease had been known in the Orient from antiquity, it became strikingly common in certain areas during the nineteenth century. It became endemic in prisons, sanitaria, aboard ship, in army camps, and in certain geographic localities. When KanehiroTakaki entered the Japanese Navy in 1872 as a young medical officer he found that at one time threefourths of the hospitalized seamen suffered from beriberi. He had learned from his father, a member of the Imperial Palace guard, that an epidemic of the disease had killed many guardsmen in 1862. This group had referred to the provision box as the kak'ke (beriberi) box, presumably associating the disease with food.l1 Takaki found medical handling of the disease in the navy to be traditional: "purgativesand digitalis for edema and palpitation, etc.; strychnine, iron, etc., for numbness and paralysis; tincture of aconite for hyper-sensibilityof muscles; and purgatives and venesection for acute cases." 17 In 1875

Takaki was able to undertake a five-yearperiod of study in the St. Thomas Hospital Medical School in London. On his return to Japan he was made director of the Tokyo Naval Hospital. Conditions regarding beriberi were unchanged except that growth of the navy meant more seamen, more beriberi cases, and more deaths. He quickly set up a study program aimed toward determining if environmental factors played a role in the incidence of the disease. By 1883 he had leamed that while working hours, sanitation, clothing, and housing were similar everywhere,there was a marked difference in the food supplied the seamen. By analyzing typical diets Takaki observedthat the intake of nitrogenousmaterial was insufficientto replace the nitrogenous output. He concluded that the carbohydrate intake was too high. Arguing that the nitrogen-to-carbonratio in the food 15. Ruth A. Guy, "The History of Cod-liver Oil as a Remedy," Am. J. Dis. Children, 26 (1923), 112-116. 16. K. Takaki, "Three Lectures on the Preservation of the Health Amongst the Personnel of the Japanese Navy and Army,"Lancet, 1 (1906), 1369-1374. 17. Ibid.,p. 1370.

6

Conflictof Conceptsin EarlyVitamin Studies should be at least 1:15.5, he found the actual ratio in naval diets to range between 1:17 and 1:32. Further, the greater the differentialbetween nitrogen and carbon, the greater the prevalence of beriberi. Takaki'srecommendationof a changed diet, made in 1882, was resisted, partly on the grounds of troubles known to have occurredin the Italian navy when the diet was changed drastically,but primarily on the grounds of increased cost. Soon thereafter, Takaki requested an investigation of the deplorable record of the training ship Riujio which, on a cruise of 272 days, reported 169 cases of beriberiwith 25 deaths in a crew of 276 men. The diet provided a nitrogen-to-carbonratio of 1:28 for sailors, 1:20 for officers.Despite opposition,Takaki received authorizationto send the Tsukuba on a similar cruise. By replacing some of the rice with condensed milk and meat it was possible to maintain a nitrogen-to-carbonratio of 1:16. During the cruise of 287 days there were 14 cases of beriberi and no deaths in a crew of 262 men. The men who contracted the disease had been unable to take condensed milk or meat, and hence had not maintained a high protein level. On the basis of Takaki's studies the Japanese Navy introduced a new diet in 1884. By substituting barley and meat for part of the rice in the traditional diet, it was possible to bring the disease under control. The Army adopted the revised diet in 1885 with similar beneficial results, although there was serious backsliding during the Sino-JapaneseWar (1894-1895) and the RussoJapanese War (1904-1905).18

In 1886 the Dutch governmentsent a commission consisting of C. A. Pekelharing, professor of pathology, and C. Winider, reader in neurology, both of the medical faculty at the University of Utrecht, to the East Indies to establish the cause of beriberi. Christian Eijkman, whom they had met in Robert Koch's laboratory in Berlin, accompanied the commissioners as an assistant. Winkler quickly established the disease to be a form of polyneuritis, in agreement with conclusions reached earlier in Japan. Bacteriological studies led to the isolation of polymorphic bacteria from the blood of patients. When Pekelharing and Winkler returned to Europe in 1887 their report19 tenta18. K. Takaki, "On the Cause and Prevention of Kak'ke," Sei-I-Kai Medical J., 4 (1885), 29-40; also see fn. 16 above, incL pp. 1451-1455 and 1520-1523. The lectures published in The Lancet give much more detail than Takaki's original publications in Sei-I-Kai. 19. C. A. Pekelharing and C. Winkler, "Mittheflung uber die Beriberi," Deutsch. med. Wochschr., 13 (1887), 845-848.

7

AARON J. IHDE AND STANLEY L. BECKER

tively attributed the cause of the disease to a coccus isolated from the air of a barracksconsideredto be infected. Eijkman remained in Batavia as director of the new laboratory of bacteriology and pathology. He soon observed that a polyneuritis similar to beriberiin humans was apparentin the chickens housed on the laboratory premises. The hens were noticed to have an unsteady gait and difficulty in perching; they soon showed leg weaknesses and abnormalbending of the knee and ankle joints; the birds finally collapsed and remained lying on their sides with weakness of wing muscles becoming evident when the birds struggled to right themselves; soon the birds could eat only with assistance; paralysis of the respiratory muscles followed; the comb became cyanotic; the eyes were coveredby the nicitating membrane;the temperaturefell. Attempts to transmit the disease, using material from diseased birds, were iMconclusive,in part because even the birds used as controls were diseased. Suddenly, the birds which were still alive recovered. Investigationrevealed that the chickens had had a change of feed. From 17 June to 27 November the laboratorycaretaker had fed the chickens cooked rice leftovers obtained from the nearby army hospital kitchen. When a new cook took over, he refused to release military rice for civilian chickens. Thereupon, unmilled rice was procuredfor the birds and the disease disappeared.The disease had been noticed on 10 July; it disappearedin the last days of November. Planned experiments on chickens verified the relationship between the disease and diet. Chickens showed symptoms of polyneuritisafter 3-4 weeks on a diet of cookedwhite rice. Controls fed unpolished nrceremained in good health, and diseased birds could be cured by substitution of unpolished rice.20Polyneuritis was also caused by feeding other starchy substances such as sago or tapioca. Meat had preventative and curative effects but rice polishingswere superior. Before returning to Europe im 1896, Eijkman directed A. G. Vorderman, medical inspector of Java, to make a study of human beriberi in the prisons of the island. Vorderman'sreport 21 revealed a high incidence of beriberi in pnsons where 20. C. Eijkman, 'TPolyneuritis bij hoenderen," Geneesk. T. Ned.-Ind., 30 (1890), 295-334; 32 (1893), 353-362; 33 (1893), 163-217; 36 (1896), 214269. Also see Eijkman's Nobel Lecture, Nobel Lectures, Medicine or Physiology, 1922-1941 (Amsterdam, 1966), pp. 199-207. 21. A. G. Vorderman, Onderzoek naar het verband tusschen den aard

dir rijstoeding in de gevangenissen op Java en Madoera en het voorkomen van beriberi onder de geinterneeden (Batavia, 1897); "'Toelichting op mijn beriberi verslay.' Geneesh. T. Ned.-Ind., 38 (1898), 47-62.

8

Conflict of Concepts in Early Vitamin Studies polished rice was the principal component of the diet, a low incidence where unpolished rice was used. Eijkman's experiments were continued in Java by Gerrit Grijns, who found that certain native beans, particularly the "katjang idjo," were preventative of polyneuritis. He also showed that the protective character of rice polishings, or katjang idjo, was destroyed by prolonged heating above 1100C. Contrary to Eijkman, who believed beriberi to be caused by a toxin in the endosperm of rice and prevented by an antitoxin in the polishings, Grijns believed the disease was due to deficiency of an essential nutrient, speaking of the lack of a "protective factor" in 1901.22

Pellagra has a shorter known history than the other deficiency diseases but its incidence has always been associated with food, particularly the consumption of maize, or Indian corn. Niles23 tells us that Baruino, in a medical treatise of 1600, has reference to a skin disease occurring among the American Indians which may have been pellagra. Baruino attributed the disease to the extensive use of corn. Very shortly thereafter, Francisco Scipione, the Italian poet, described a similar disease affecting men and horses which he attributed to spoiled grain. These references, however, may easily have been to other disorders, and it is not easy to ascertain whether pellagra was present in Europe before the introduction of Indian corn. Maize was introduced into Spain between 1680 and 1700, and symptoms of pellagra began to be described, but the disease was confused with gastrointestinal disorders, eczema, leprosy, scurvy, and nervous and mental diseases. The earliest clear account of the disease is that of Gaspard Casal,24 who described it fully in 1735, using the term "Mal de la Rosa." The disease appeared in northern Italy about this time, and Francesco Frapolli25 adopted the name pellagra (rough hands) which was in use among the peasants. The disease also became endemic in parts of France, Austria-Hungary, and Egypt. Everywhere the disease was associated with corn, particularly the consumption of spoiled corn. 22. G. Grijns, "Beriberi on rijstveeding," Geneesk. T. Ned.-Ind., 41 (1901), 3; Mededeelingen v. h. Lab. Path. Anat. en Bakt. te Wetlevreden (1900); Researches on Vitamins, 1900-1911 (Gorinchem, 1935). 23. Niles, fn. 9 above, p. 13. 24. G. Casal, Historia natural, y medica de el Principado de Asturas (Madrid, 1762), P. 327. For an English translation see R. H. Major, Classic Descriptions of Disease (Springfield, Ill. 3rd ed., 1945), pp. 607, 610-612. 25. F. Frapolli, Animadversiones in Morbum, vulgo Pelagram (Milan, 1771) p. 7; see Major ref. 24, pp. 612-614.

9

AARON J. IHDE AND STANLEY L. BECKER

The first reportedinstance of the disease in the United States was in 1864 when cases were observed almost simultaneously in Utica, New York, and Somerville, Massachusetts. Descriptions of prison conditions toward the end of the Civil War suggest that the disease may have been widespread therein. The disease almost certainly was endemic in the South during the postwar decades, but clean-cut descriptions are few and the disease was usually diagnosed as unusual forms of malaria, syphilis, tuberculosis, eczema, and various forns of mental diseases. Only after the twentieth century began did the symptoms combining dermatitis, diarrhea, and dementia come to be diagnosed as pellagra. By then the disease was widespread in the agriculturalsections of the South and was a severe problem in mental hospitals.26 FAILUREOFSYNTHETICDIETS Parallel with the dietary observationswhich were developing through the work of medical investigators toward the end of the nineteenth century were results of animal experiments which were consistently revealing the inadequacy of highly purified or peculiarly unbalanced diets. When McCollumwas puzzling over the iMadequaciesof single-grainrations being fed to cows at the University of Wisconsin, he found 13 reports in the literature between 1873 and 1906 revealing failure of experimental animals to grow and maintain satisfactory health when fed diets containing presumably sufficient amounts of fats, carbohydrates,proteins, and mineral salts.27 Additional instances, such as Pekelharing'spaper of 1905, came to light later. In all instances there was a failure to follow up the obvious (?) consequencesof the experiments. The earliest studies of this nature were oriented toward an understanding of mineral requirements. Josef Forster,28an assistant in physiology at Munich, fed dogs on muscle which had been extracted to remove all water-solublesubstances (ash was 0.8 percent), plus sugar, starch, and fat in order to observe 26. Niles, fn. 9 above, pp. 25-33. 27. E. V. McCollum, A History of Nutrition (Boston, 1957), p. 201; From Kansas Farn Boy to Scientist (Lawrence, Kansas, 1964), p. 117; "My Early Experiences in the Study of Nutrition," Ann. Rev. Biochem., 22 (1953), 1-16. For McCollum's list and the citations thereto see the latter reference, pp. 6 and 15. 28. J. Forster, "Versuche uber die Bedeutung der Aschenbestandtheile in der Nahrung," Zeitschr. f. Biologie, 9 (1873), 297-380.

10

Conflictof Conceptsin EarlyVitamin Studies any disturbance of the muscular and nervous systems under nearly mineral-free conditions. He observed that death occurred earlier than when dogs were completely starved. He concludedthat certain minerals are essential to life. Gustav von Bunge, physiologist at the University of Dorpat, hypothesized that Forster'sdogs on the low mineral diet died earlier than starved dogs because they were being poisoned by the sulfuric acid formed in the body by oxidation of the sulfur in the protein that was fed. His student Nicholas Lunin29 tested the hypothesis on mce, which were fed casein, cane sugar, and water. On this diet they died in 11 to 21 days. When enough sodium carbonatewas added to neutralize sulfuric acid equivalent to the sulfur present in the diet, survival was between 12 to 30 days. Results were no better when potassium carbonatewas used. When mice were fed casein, milk fat, milk sugar, and a salt mixture resembling the ash of milk they showed no improvementin survival time, but mice given milk as their sole food remained in good health for the duration of the experiment (two months). Lunin said in his dissertation, "Mice can live under these conditions when receiving suitable foods (e.g., milk), but as the expenrmentsshow that they cannot subsist on proteins, fats and carbohydrates,salts and water, it follows that other substances indispensable for nutrition must be present in milk besides casein, fat, lactose, and salts."30 In 1885 Bunge joined the medical faculty at the University of Basle where he continued his interest in the importance of inorganic substances in nutrition. His student, Carl A. Socin,31 utilized simplifieddiets in order to study the role of several iron compounds. Feeding a diet of blood serum, cellulose, sugar, starch, fat, and milk ash, Socin supplied iron in the form of ferric chloride, hemoglobin,hematin, or hematogen. (The latter was a nitrogenous substance prepared from fat-free egg yolk by digestion with artificialgastric juice. It contained phosphorus and iron. Bunge believed it to be of great physiological significance.) The mice on these diets failed to survive more than 32 days regardless of the source of iron; mice on a control diet of egg yolk, starch, and cellulose appearedhealthy during the full experimental period of 99 days. The egg yolk, according 29. N. Lunin, "Ueber de Bedeuting der anorganischen Salze fur die Ehrnihrung des Thieres," Zeitschr. physiol. Chem., 5 (1881), 31-39. 30. Lunin, ibid., p. 38; translation from McCollum, A History of Nutrition, p. 204. 31. C. A. Socin, "In welcher Form wird des Eisen resorbert?" Zeitschr. physiol. Chemie, 15 (1891), 93-139.

11

AARON J. IMDE AND STANLEY L. BECKER

to Socin, apparently contained an essential substance of unknown nature. The conclusions of Lunin and Socin were not pursued by them, nor did they have an impact in Bunge'slaboratory.Nicholas Lunin (1853-1936) became a staff member at the Hospital of Prince Oldenburgin St. Petersburgwhere he had an active career as a pediatrician.32Soicm likewise abandoned the field of nutrition. Bunge himself was concemed with the role of minerals in metabolism and, in the several editions of his textbooks,33sought to develop these relationships. In accordance with the widely held belief that animal cells were incapable of synthesis of complex organic substances he sought to establish the presence of organic forms of mineral elements in foods. He was particularly concerned about the precursors of iron in hemaglobin, and his students, Hausermann and Abderhalden, carried out feeding experiments on anemic animals. In studies in which diets were supplementedwith hemoglobin, hematin, or iron salts, they concluded that organically bound iron was essential. WHYTHETIMELAGIN ACCEPTANCE OFTHETRACE NUTRIENTCONCEPT? We have observed that by 1900 there was an accumulation of evidence for the need for dietary components other than proteins, fats, carbohydrates,and minerals. Yet it was another twelve years before serious statements suggesting that trace organic nutrients were essential began to appearin the medical literature. Why was there a time lag of over a decade before there began to be a slow recognition in nutrition circles that the gross nutrient materials alone were not adequatefor growth and maintenanceof animals or human beings? An examination of the thinking of the time reveals that at least five commonly held concepts delayed the developmentof the trace nutrientconcept. These were: 1. The germ theoryof disease 2. Toxins as the cause of disease 32. S. A. Goldblith and M. A. Joslyn, eds., Milestones in Nutrition (Westport, Conn., 1964), p. 97. 33. G. von Bunge, Lehrbuch der physiologischen und pathologischen Chemie (Leipzig, 1887; 4th ed., 1898) was translated into five languages, including English. For biographical information on Bunge, see C. M. McKay, "Gustav von Bunge," J. Nutrition, 49 (1953), 3-19, and H. Schriefers, Dictionary of Scientific Biography (New York, 1970) I, 585-586.

12

Conflict of Concepts in Early Vitamin Studies 3. The Liebig-Voit views on nutrition a) Adequate plastic foods b) Adequate albuminous foods 4. The Schmidt-Bunge views on minerals in nutrition 5. Proximate Principles in Food Analysis If these five factors are carefully analyzed we find that they were quite capable of leading medical scientists in directions which caused them to ignore the possible role of organic trace nutrients as factors in the avoidance of certain diseases. In fact, appreciation of such trace nutrients would ultimately come primarily from the activities of agricultural chemists rather than from human physiologists. Nevertheless, chemists were also delayed in their recognition of the role of food in preventing deficiency diseases by adhering too long to simplistic nineteenth-century views of nutrition and placing excessive faith in proximate chemical analysis. Germ Theory of Disease Following the improvement of the microscope, which occurred in the first third of the nineteenth century, the cell became firmly established as the fundamental unit in animal and plant life and the science of microbiology was born. Although bacteria had been described by Anton van Leeuwenhoek34 in letters dating from 1674, the pre-nineteenth-century microscope was inadequate to advance knowledge of such organisms persuasively. Only with the improved instrument could microbiology advance. In scarcely more than a generation fermentation became clearly associated with unicellular forms of life, spontaneous generation suffered still another setback, and diseases became associated with specific causative organisms. Although Agostino Bassi had associated the muscardine disease in silkworms with a minute fungus by 1836 and Johann Schonlein had associated a certain skin disease with a fungus in 1839, it was actually the work of Louis Pasteur between 1860 and 1870 that focused attention on the role of microorganisms in causing disease. Pasteur had already demonstrated that different kinds of fermentation were associated with specific microorganisms. Through his studies of fermentations producing ethyl alcohol, amyl alcohol, butyl alcohol, lactic acid, 34. C. Dobell, ed., Antony van Leeuwenhoeh and his Little Animals, (New York, 1958), pp. 109ff. Many of Leeuwenhoek's letters were originally published in the Philosophical Transactions of the Royal Society in condensed form.

13

AARON J. IDE AND STANLEY L. BECKER

and acetic acid he became convinced of the specificityof action of particular microorganisms.When he studied the "diseases" of wine, he associated the spoilage with elongated organisms mixed with the normally present globular yeasts. His work on the p6brine disease of silkworms in 1865 clearly associated the

disease with minute bacteria infecting the worms and their food. His subsequent interest in communicable diseases fortified his belief that such diseases were caused by the presence of specificorganismsin the environmnent. The British surgeon Joseph Lister very quickly made use of the new knowledgeby introducingthe use of appropriatechemicals such as phenol to create antiseptic conditions, with a substantial decrease in deaths from postoperative infections. Despite opposition, surgery soon took notice of the role of microorganisms as a cause of infection, and aseptic techniques were coming into use within another decade. Ferdinand Cohn pioneered in the development of the new science of bacteriology, particularly in the field of classification. He encouragedRobert Koch in his early work when Koch brought to him the results of his studies on anthrax in 1876. Koch had transferredthe disease from cattle to mice, carrying the disease through a sequence of mouse generations, and recovering the baciflus at the end with its virulence unabated. He learned to cultivate the bacifius outside the animal body, using blood serum at body temperatureas a medium. He also pioneered in the development of staining techniques and introduced the use of solid media, gelatin, and agar-agar for the cultivation of bacteria. Introducingthe postulates that a causative organism must be isolated from an animal suffering from the disease, must be carried as a pure culture through repeated transfers on synthetic media, and must be able to cause the disease when inoculated into a healthy animal, he identified the bacteriaresponsiblefor tuberculosisin 1882, and for cholera in 1883. A whole generation of microbe hunters received their training in his laboratory (Gaffky, Kitasato, Behring, Ehrlich). Parallel with Cohn's work on bacteria, Karl Leuckart was carrying on studies of animal parasites such as tapeworms and flukes, and showed that diseases such as trichinosis are caused by tiny multicellular animals.

Following Koch'swork on the anthrax bacillus, Pasteur confirmed the spore-formingcharacteristics of the organism. He also recognized that the few animals who recovered from the disease had acquired an immunity to further attacks and he 14

Conflict of Concepts in Early Vitamin Studies was successful in producing attenuated anthrax bacilli by exposing them to heat. Sheep inoculated with the attenuated bacilli in 1881 developed an immunity which enabled them to survive inoculation with virulent anthrax organisms. Pasteur went on to develop immunization techniques for chicken cholera and rabies. In the case of the latter disease, he was never able to isolate a causative organism, but he nevertheless had faith that one must be there. In 1883 Koch traveled in Asia to study human cholera and bubonic plague and to Africa to study sleeping sickness. He showed, at the turn of the century, that bubonic plague was transferred by a louse carried by rats and that sleeping sickness was transmitted by the tsetse fly. At about that time the role of the Anopheles mosquito as a transmitter of malaria was clearly established as a result of the studies by investigators from France (Laveran), Italy (Marchiafava, Golgi, Bignami, Bastianelli, Grassi), and Britain (Manson, Ross), and the life cycle of the malarial parasite was established. As early as 1877 Manson had established that the parasite causing elephantiasis is transmitted by a Culex mosquito. All of those countries having colonial interests in the tropics supported vigorous investigation toward the control of such diseases. Significantly, virtually all of the research was directed toward the isolation and understanding of a causative organism. The development of vaccines for the creation of immunity toward specific diseases became a popular and fruitful area of research toward the end of the century. Emil von Behring, working in Koch's laboratory in 1890, discovered that it was possible to immunize an animal against tetanus by inoculating it with graded doses of blood serum taken from another animal afflicted with the disease. A portion of the serum from the immunized animal (the antitoxin) then conferred temporary immunity in another animal. Behring believed that a cure for diphtheria might be prepared by using antibodies produced in animals inoculated with the germ which had been identified by Edwin Klebs and Friedrich L6ffler. Together with Paul Ehrlich, Behring developed the technique of preparing and using diphtheria antitoxin in 1892. It proved remarkably effective not only in preventing the dread childhood disease, but even in curing the disease after it had begun. Ehrlich went on to develop chemical agents which were active in the control of certain disease-producing microorganisms, specifically the dye Trypan red for the treatment of trypanosomal diseases such as

15

AARON J. IHDE AND STANLEY L. BECKER

sleeping sickness, and arsenic-containing organic compounds for the treatmentof syphilis. The germ theory of disease proved a dramatic breakthrough in medicine. By 1906 the causative organisms of more than twenty diseases had been isolated and established according to Koch's postulates.35 The notion that a disease was caused

by a specific microorganismproved exceedingly attractive,particularly when there were successes in control associated with antisepsis and asepsis, serum therapy, chemotherapy, and man-

agementof insect vectors. There has been a tendency throughoutmedical history to be attracted by a unitary view of disease-that is, to believe that disease can be explained and treated on the basis of a simple and single point of view. The germ theory of disease proved to be vastly more successful than any previous medical concept. With the emphasis which began to be placed on sanitation in the period from 1870 onward, there was a new success in medical practice and surgery which created a temptation to believe that microorganisms might be responsible for all diseases and that treatment simply consisted of control of the causative microorganisms. Thus, it is hardly surprising that the germ concept proved a major barrier to the recognition and study of deficiencydiseases.36 In the case of every disease mentioned by Funk, claims were published for the discovery of a causative organism. Vedder37 cites a lengthy list of authors claiming the discoveryof a causative organism in his book on beriberiin 1913. Five investigators attributed the disease to protozoa, three to nemathelminthae, 15 to some form of bacteria, and one believed the disease attributable to a fungus on moldy rice. We have already noted that the Pekelharing task force was sent to Java to locate the causative organism. Pekelharingand Winkler actually reported such an organism upon their return,88while Eijkman sought 35. See C. Singer and E. A. Underwood, A Short History of Medicine, 2nd ed., (Oxford, 1962), p. 391, for a chronological listing of discoveries of disease-producingbacteria. 36. For a good study of this problem see R. H. Follis, Jr., "Cellular Pathology and the Development of the Deficiency Disease Concept," Bull. Hist. Med., 34 (1960), 291-317. 37. Vedder, fn. 7 above, pp. 89 and bibliography. 38. Pekelharing and Winkler (see fn. 19 above); also "Mittheilung ueber die Beriberi," Centralblatt fur Bacteriologie, 3 (1888), 77-86; and Reserches

sur la nature et la cause du beriberi et sur le moyens

combattre (Utrecht, 1888), trans. J. Cantlie (Edinburgh, 1893).

16

de la

Conflict of Concepts in Early Vitamin Studies to transmit the disease to healthy chickens until he was fortunate in making the association with unpolished rice. Scurvy was likewise associated with bacterial infections. Stewart has said, One factor which undoubtedly held up the development of the concept of deficiency diseases was the discovery of bacteria in the nineteenth century and the consequent preoccupation of scientists and doctors with positive infective agents in disease. So strong was the impetus provided by bacteriology that many diseases which we now know to be due to nutritional or endocrine deficiencies were, as late as 1910, thought to be "toxaemias"; in default of any evidence of an active infecting micro-organism they were ascribed to the remote effects of imaginary toxins elaborated by bacteria.39 As late as 1916 Jackson and Moore40 claimed to have isolated a diplococcus from the tissues of scorbutic guinea pigs. After cultivating the organism in the laboratory, they injected it into healthy guinea pigs and reported hemorrhages. They were able to isolate the diplococcus from the lesions. The Italian physiologist Morpurgo4' argued strongly for the causative role of a diplococcus in rickets after he isolated the organism from rats in which an outbreak of rickets occurred spontaneously. In 1911 J. Koch42 injected a streptococcus longus into dogs and observed swellings and deformities at various joints. The infection theory was also popular in the case of pellagra. In his treatise on the disease, Roberts48 discusses at length the pathological and ecological evidence of infection. Dr. Louis Sambon of the Liverpool School of Tropical Medicine set up a series of postulates to prove that pellagra is a parasitic dis39. C. P. Stewart in Stewart and Guthrie, fn. 12 above, pp. 408-409. 40. Leila Jackson and J. J. Moore, "Studies on Experimental Scurvy in Guinea Pigs," J. Infectious Diseases, 19 (1916), 478-510. 41. B. Morpurgo, "Ueber eine infectiose Form der Osteomalacie bet weisssen Ratten, Beitrage path, Anat. u. Path., 28 (1900), 620-626; also see "Durch Infektion hervorgerufene malacische und rachitische Skeletverainderungen an jungen weissen Ratten," Centralblatt allg. Path. u. path. Anat., 13 (1902), 113-119. 42. J. Koch, "'Jntersuchungen uber die Lokalization der Bakterien, das Verhalten des Knochenmarkes und die Veraenderungen der Knochen, inbesondere der Epiphysen bei Infektionskrankheiten. Mit Bemerkungen zur Theorie der Rachitis," Zeitschr. fur Hyg. 69 (1911), 436-459. 43. S. R. Roberts, fn. 9 above, pp. 247-265.

17

AARON J. IBDE AND STANLEY L. BECKER

ease.44When Joseph Goldbergerbegan his studies on pellagra in the United States in 1914 his deficiency ideas were vigorously resisted, even after he had failed to transmit the disease to himself and human volunteers by injection, inhalation, or swallowing of blood, nasal secretions, urine, feces, or scales of skin taken from pellagrouspatients.45 Thus, each of the important deficiency diseases was associated with positive infectious agents, in line with the prevailing medical dogmasof the times. Follis has said, As a result of the tremendous influence of these positive agents, the bacteria and their products, it was difficult to think in terns of negative causes of disease. Medical science,

just as has the law, had difficulty even considering, much less proving, a negative, particularly in the face of all the positive factors. Even as late as 1907, Marine has said that he "frequentlyheard the criticism that it was difficultto conceive of a deficiency or absence of something causing something." 46

In defense of the medical men it must be said that there were numerous factors working against the unambiguous recognition of these diseases as attributableto a dietary deficiency. In experimental animals and in human beings these diseases are rarely uncomplicated.When a food is lacking in quality there is frequently a multiplicity of shortcomings,not the lack of a single essential substance. The later difficulties of the nutritionists in designing rations lacking only a single factor attest to the magnitude of this problem.Furthermore,an animal suffering from a deficiencydisease is in a weakened and frequently inflamed condition. It is therefore readily susceptible to the invasion of microorganisms. Searchers for bacteria inevitably found them, and when using faulty experimental techniques, persuaded themselves that the microorganismscaused the disease instead of realizing that the unhealthy state of the animal preventedresistance to the invasion of parasites in the environment. Toxins as the Cause of Disease

It had been recognized from antiquity that certain specific substances have the capacity to cause illness and death. Use of 44. According to Niles, fn. 9 above, pp. 52-54. 45. J. Goldberger, "The Transmissibility of Pellagra. Experimental Attempts at Transmission to the Human Subject," U.S. Public Health Reports, 31, no. 46 (1916), 3159-73. Reprinted in M. Terris, ed., Goldberger on Pellagra (Baton Rouge, La., 1964), pp. 95-110. 46. FoMls,fn. 36 above, p. 307.

18

Conflict of Concepts in Early Vitamin Studies arsenicals figures prominently in the history of political and social murder. Knowledge of the toxic properties of plants containing certain alkaloids, glucosides, and resins was of long standing, as was knowledge of the dangers from the bites and stings of certain reptiles and insects. No medical theories were able to ignore the effects of toxic substances. The development of knowledge of microbiology fortified the field of toxicology since it quickly became evident that in some cases illness was attributable, not to any direct action of a microorganism, but to the effect of toxins produced by it. In some cases the toxin was produced by the organism after invasion of the body; in others by its action in food outside the body. August Gaertner, a military surgeon, became deeply interested in hygiene and food bacteriology after studying under Koch. In 1888 he discovered Salmonella enteritidis, an organism whose toxin in foods causes severe digestive upsets. In 1896 Emile van Ermengen, professor of bacteriology at the University of Ghent, isolated Clostridium botulismum, the organism responsible for the production of one of the most toxic substances known. At the end of the nineteenth century there was also a great deal of interest in the alleged production of "ptomaines" by intestinal bacteria, and autointoxication of the body through absorption of such intestinal toxins. It is not surprising that the deficiency diseases were frequently caught up in the toxin concept. We recall that Eijkman attributed beriberi to a toxin in the endosperm of rice, arguing that the polishings must contain an antitoxin. In his treatise on beriberi, Vedder47 makes reference to authorities attributing the disease to inorganic toxins (arsenic, oxalate, carbon dioxide) as well as to organic toxins produced by bacteria or even by higher plants. In his book on diseases of the bones, Marfan48 attributed rickets to a variety of poisons, including some produced by bacteria. Cheadle and Poynton49 believed the disease was due to toxic substances elaborated in farinaceous foods. Pellagra was widely believed to be due to the consumption of spoiled maize. Casal held this view as early as 1762, and the idea remained popular up to the very time that pellagra was established to be a deficiency disease.50 Various molds were particularly suspect. 47. Vedder, fn. 7 above, pp. 88-89. 48. A. B. Marfan, Maladies des os (Paris, 1912). 49. W. B. Cheadle and F. J. Poynton, "Rickets" in Allbutt's System of Medicine, (London, 1901). 50. For a summary of this view see Niles, fn. 9 above, pp. 34-44.

19

AARON J. IHDE AND STANLEY L. BECKER

The Liebig-VoitViews on Nutrition Paralleling the germ and toxin concepts of disease was the persistence of nutrition concepts developed by Justus von Liebig in his book, Animal Chemistry,51published in 1842. These views were extended and systematized, and sometimes corrected, by Karl von Voit, a former Liebig student and a leading investigator of nutritional problems during the last half of the nineteenth century. These views had a profoundinfluence, both in agriculturalcircles and amonghuman physiologists. Liebig emphasized the idea that growth and health of an animal would be satisfactory if the food supplied 1) an adequate quantity of heat-producing foods, and 2) a sufficient quantity of albuminousmaterial for replacementof nitrogenous materialdestroyedduringmuscular activity.52 Soon after publication of Liebig's book, there was intense interest in respiration calorimetry, reflecting a sympathetic reaction to the interest of physicists in energy relationships, particularlythe concept of conservationof energy. The pioneering work on animal respiration by Victor Regnault and Jules Reiset was followed in the next decade by that of Voit and his school. Voit and Pettenkoferwere using a calorimeteradequate for the study of an adult human by 1866.53During the course of these studies it became apparent to Voit in 1861 that, contrary to Liebig, muscular activity did not increase the rate at which proteinswere metabolized. Since proteins are unique among major food constituents in containing nitrogen, there was a special interest in these sub51. Liebig, Justus, Animal Chemistry or Organic Chemistry in its Application to Physiology and Pathology, edited from the author's manuscript by Wm. Gregory (London, 1842). A German edition was published simultaneously in Braunschweig and an American edition shortly thereafter in Cambridge, Mass. A readily available and useful edition is the facsimile reprint of the Cambridge edition of 1842 (New York, 1964). This edition has a long and excellent introductory essay by Frederick L. Holmes. For a critique of the influence of Liebig's book see Holmes, above; F. R. Moulton, ed., Liebig and After Liebig (Washington, 1942); A. J. Ihde, "An Inquiry into the Origins of Hybrid Sciences: Astrophysics and Biochemistry," J. Chem. Edu., 46 (1969), 193-196; S. L. Becker, fn. 4 above. The latter work has a concise summary of Liebig's

nutritional views (pp. 4-7) and of the influence of these views on later physiologists (pp. 8-11). 52. Liebig, Animal Chemistry, pp. 60-92. 53. On the history of animal calorimetry see G. Lusk, "A History of Metabolism," Endocrinology and Metabolism, L. F. Barker, R. G. Haskins

and H. 0. Mosenthal, eds. (New York, 1922), III, 3-78. E. Mendelsohn, Heat and Life (Cambridge, 1964) has a good treatment of the problem of animal heat in the period before the rise of thermodynamics.

20

Conflictof Conceptsin EarlyVitamin Studies stances. The Dutch chemist Gerardus Mulder introduced the word "protein,"for "of first importance"in 1838, following a suggestion of Berzelius.54He developed the idea of a protein radical with the formula C40H62NA0012. Differencesin individual plant and animal proteins were looked upon as combinations of the protein radical with atoms of sulfur and phosphorus. Casein was lOPr + S; fibrin and egg albumin were lOPr + SP; gluten was lOPr + S2; blood albumin, 1OPr+ SYP. Protein precipitates with tannic acid, hydrochloric acid, or lead oxide were formulated in the same manner, the supposition being made that a double decompositionoccurredin which the sulfur and phosphorouswere displaced.A5 Work in Liebig's laboratorythrew doubt on the radical concept since sulfur-free protein preparations could not be prepared, and Mulder'sconcept fell into discard. Liebig, however, held that fibrin, casein, and albumin, the chief proteins of nature, had the same composition56and this idea was held implicitly or explicitly during the remainder of the century in most physiological and agricultural circles. Liebig was responsible for the idea that the albuminousmaterials of plants were ingested directly in the animal body to become the albuminous materials of blood and muscles. Although subsequent physiological work in various quarters led to gradual recognition of the role of digestive enzymes in bringing about the degradation of food components to simpler units, the action was looked upon as a solubilizing effect without breakdownto small units. This was particularlytrue with respect to the digestion of proteins. Although ten naturally occurring amino acids were known by 1880, only six of these were associated with protein hydrolysis. By 1900 five more amino acids were known and now 13 were found associated with protein hydrolysis.57When Emil Fischer introduced the ester fractionation technique for the separation of amino acids and developed the peptide hypothesis of protein structure there was still little appreciation 54. H. B. Vickery, "The Origin of the Word Protein," Yale J. Biol. Med., 22 (1950), 387-393. 55. G. J. Mulder, The Chemistry of Vegetable and Animal Physiology, translated from the Dutch by P. F. H. Fromberg (Edinburgh, 1845), p. 73. Also see Berzelius' Jahres-Bericht, 18 (1839), 534; 19 (1840), 639; and 27 (1848), 569. 56. 3. Liebig, "Teber die stickstoffhaltingen Nahrungsmittel des Pflanzenreichs," Annalen der Chemie, 39 (1841), 129-160. Also see N. Laskowski, "Ueber die Protein Theorie," ibid., 58 (1846), 129-166. 57. H. B. Vickery and C. L. A. Schmidt, "'The History of the Discovery of the Amino Acids," Chem. Reviews, 9 (1931), 169-318.

21

AARON J. UIDE AND STANLEY L. BECKER

of the complexity of proteins, or of the differences between them. The extensive studies on the decompositionof proteins which were made in the laboratoriesof Willy Kiihne at Heidelberg and Russell Chittenden at Yale were aimed, for two decades, toward the understanding of major protein fragments (albumoses, antipeptones, hemipeptones). It was recognized that food components were absorbedfrom the intestines only when in a soluble fonn. Since the peptones were diffusible, it was felt that this degree of degradation was sufficient for absorption into the blood stream. Further digestion to amino acids would be a waste of physiological energy. This point of view was a natural one before the discovery of erepsin by Otto Cohnheim in 1901.58This enzyme, which was ultimately shown to be a mixtureby the workof E. Waldschmidt-Leitz,Max Bergmann, and others from 1930 onward, proved to be responsible for the final steps in the hydrolysis of proteins to amino acids. Further,it was only in 1913 that analytical methodology was adequate to permit Emil Abderhalden59to establish the presence of amino acids in the blood.80 The Schmidt-BungeViews on Mineralsin Nutrition The mineral problem was a somewhat special one. It had been recognizedin the eighteenth century that certain inorganic elements are present in plants and animals. Studies of growth in synthetic soils revealed that plants can utilize such elements m the form of inorgamiccompounds. There was, however, a reluctance to accept the idea that animals were able to utilize such elements in inorganic form. Liebig gave attention to the problem but the ideas were more fully developed by a former Liebig student, Carl Schmidt, at Dorpat and by his student, Gustav von Bunge, at Dorpat and Basel. As early as 1850, Schmidt's analysis of blood showed that most of the sodium was in the plasma while most of the potassium was in the cells. During the next thirty years there was a steady flow of publications from Dorpat on the subject of minerals in living tissues. 58. 0. Cohnheim, "Die Umwandlung des Eiweiss durch Darmwand," Z. physiol. Chem., 33 (1901), 451-465; "Weitere Mittheilung uber das Erepsin,"ibid., 35 (1902), 134-140. 59. E. Abderhalden, "Der Nachweis von freien Aminosauren im Blute unter normalen Verhaltnissen," ibid., 88 (1913), 478-483. 60. For a good study of the whole problem of protein composition see H. B. Vickery and T. B. Osborne,"A Review of Hypotheses of the Structure of Proteins," Physiological Reviews, 8 (1928), 393-446, esp. pp. 395-400.

22

Conflict of Concepts in Early Vitamin Studies Bunge, who became interested in sodium chloride metabolism during his student days, came to believe it to be the only inorganic nutrient which was utilized directly as the salt. Such elements as iron, calcium, and phosphorus, he believed, must be supplied to the animal in the form of organic compounds. The feeding experiments carried out in his laboratory by Socin were initiated to shed light on the source of iron in hemoglobin. The experiments of both Lunin and Socin, although designed to shed light on the iron problem, pointed clearly to the inadequacy of synthetic diets. The clue was not pursued in Bunge's laboratory. In his Nobel Award Address Hopkins declared: . . . Bunge, though in his well-known book he remarks that it would be worth-while to continue the experiments which had suggested the existence of unknown nutritional factors, was, as I happen to know, himself inclined to disbelieve in them. He thought that the real error in the synthetic diets used by his pupils (which was, so to speak, "dissected milk") was that the method of its preparation had involved the separation of inorganic constituents from certain organic combinations in which latter form alone could they adequately subserve the purposes of metabolism.0' In the case of phosphorus, significance was placed by investigators on the instances where organically bound phosphorus was present in animals: lecithin, cephalin, nucleoproteins, and phosphoproteins such as casein and vitellin. Feeding experiments on dogs, mice, pigeons, and chickens were reported by four investigators62 in 1899 and 1900. All of them sought to compare the value of phosphorus-free proteins (egg albumin, myosin, blood albunin, edestin) with phosphorus-containing proteins (casein, vitellin) as supplements to highly purified diets. In all cases the animals rapidly lost weight and died. Yet there was a failure to recognize that the problem was one of adequacy of the basal ration rather than one of source of phosphorus. This was still true in 1906 when Falta and Noggerath 61. From fn. 3 above, Needham and Baldwin, p. 194; or see Nobel Foundation, Nobel Lectures, Chemistry, 1922-1941 (Amsterdam, 1964), p. 214. 62. F. Steinitz, "Ueber das Verhalten phosphorhaltigen Eiweisskorper im Stoffwechsel," Pfliiger's Archiv Physiol., 72 (1898), 75-104; H. Zadik, "Stoffwechselversuche mit phosphorhaltigen und phosphorfreien Eiweisskorpern," ibid., 77 (1899), 1-21; R. Leipziger, "Ueber Stoffwechselversuche mit Edestin," ibid., 78 (1900), 402-422; P. Ehrlich, "Stoffwechselversuche mit P-haltigen und P-freien Eiweisskorpern," Inaug. Dissert., Breslau, 1900.

23

AARON J. IHDE AND STANLEY L. BECKER

found that the addition of nucleic acid, lecithin, or cholesterol failed to nourish their animals properly.63In 1909 McCollumM4 showed that organic forms of phosphorus are unnecessary in the animal diet. His animals synthesized all essential organic phosphates although the only dietary source of phosphoruswas calcium phosphate. At this time there was general recognition that certain inorganic elements are essential to animals but there were vast differences of opinion regarding the form in which they were utilized. There was even resistance to accepting evidence for the essentialityof unique elements such as iodine. Although there was a great deal of interest in the role of minerals in animal physiology at the turn of the century, the right questions were not being asked and experimental methodology was primitive. As a consequence, there was little progress in gaining an understanding of the role of minerals in nutrition and the concept of mineral deficiency diseases met a great deal of resistance, even in the case of anemia and goiter. Had there been greater success in establishing mineral deficiencies there might have been a greater willingness to accept the conceptof organicdeficienciesin foods. Proximate Principles in Food Analysis

Compoundingthe confusion about nutrition at the end of the nineteenth century was the reliance upon proximate principles in food analysis. In the earlier studies of biological materials, specific compounds were frequently isolated from plant and animal tissues.65These substances were given an elementary analysis in order to learn the percentageof the various elements present. From this could be calculated an empirical formula. However, such empirical formulas gave little information about the chemical nature of complex substances such as proteins, cellulose, starch, fats, and waxes. Hence, in food chemistry circles there arose a dependence upon analyses for proximate

principles. In the agriculturalexperiment stations it was more important to know the amount of moisture, mineral matter, 63. W. Falta and C. T. Noeggerath, "'Futterungsversuche mit kiinstlicher Nahrung," Beitriige chem. Physiol. u. Pathol., 7 (1906), 313-321. 64. E. V. McCollum, "Nuclein Synthesis m the Animal Body," Amer. J. Physiol., 25 (1909), 120-141. This paper has a very good review of the earlier literature dealing with the problem. 65. A. J. Ihde, Development of Modern Chemistry (New York, 1964), pp. 162, 166-170, 344-362. On organic analysis see ibid., pp. 173-179, 182-183,296-302.

24

Conflict of Concepts in Early Vitamin Studies fat, carbohydrates, and protein than to know the amounts of specific compounds present. Besides, the analytical chemistry of the day was hardly adequate to more specific tasks. The development of analysis for proximate principles arose out of the Liebig school of chemistry, particularly among those former pupils who became associated with the rapidly developing agricultural experiment stations. Johann Wilhelm Henneberg, the director of the German station at Weende, near Gottingen, was particularly active in promoting this type of analytical approach and in applying the results to agricultural problems. With his associate, Friedrich Stohmann, he developed a system of analyzing feeds and excrements of farm animals as a basis for studying digestibility and animal response to feeds. Proximate analysis lent itself very well to the study of biological materials since closely related substances responded to analytical techniques which were reasonably simple and reasonably rapid even though they lacked great specificity. Moisture was determined by oven-drying to constant weight at a temperature close to that of boiling water. Mineral matter was reported as the amount of ash remaining after incineration in a muffle furnace. Fat was reported as the material extractable with ether or some other fat solvent. Extraction of proteins from biological tissues is tedious and incomplete so advantage was taken of the fact that most proteins contain about 16 per cent of nitrogen. Nitrogen was determined by the method of Will and Varrentrapp, and after 1883 by the method of Kjeldahl.6- Multiplication of percent nitrogen by 6.25 gave percent protein. Carbohydrates were reported by difference, taking the sum of the other principles and subtracting from 100. They were usually referred to as "nitrogen-free extract." It was soon realized that carbohydrates vary enormously in digestibility, some, such as sugars and starches, being readily digested by animals, while others, such as cellulose, were comparatively indigestible. Henneberg pioneered the determination of "crude fiber" in order to make the distinction. That portion of the sample which survived successive half hour digestions at 66. J. G. C. T. Kieldahl, "Neuemethode zur Bestimnmung des Stickstoffs in organischen Korpern," Zeitschr. anal. Chem., 22 (1883), 366-382. On the history of nitrogen analysis see H. A. Schuette and F. C. Oppen, "The Determination of Organic Nitrogen: Past and Present," Trans. Wisconsin Acad. Sciences, Arts, Letters 29 (1935), 355-380; and H. B. Vickery," The Early Years of the Kjeldahl Method to Determine Nitrogen, Yale J. Biol. Med., 18 (1946), 474-516.

25

AARON J. IHDE AND STANLEY L. BECKER

the boiling point with dilute (1?4% ) solutions of sulfuric acid and sodium hydroxide was reported as crude fiber. The remainder of the nitrogen-free extract represented "digestible" carbohydrates. Proximate analysis proved very popular in the agricultural experiment stations and came to be looked upon as a basis for evaluating feedstuffs. The stations also carried out feeding studies on farm animals in order to determine the least expensive feeds for production of meat, milk, eggs, wool, and horsepower. Textbooks on feeding expounded the new scientific knowledge, all too often giving the impression of equivalency between proteins,fats, carbohydratesand minerals derived from differentplant sources. CHEMISTS AGRICULTURAL BREAKTHROUGH-THE As a consequence of examining these several concepts it becomes apparentthat the breakthroughin the role of nutrition in relation to the deficiency diseases was not to be expected from medical circles. Eijkman, who was close to solving the beriberi problem, was blinded by his bacteriological background. In fact, he had been sent to the Dutch Indies for the express purpose of finding the causative organism for beriberi. As a result of his experiments on chickens, he was led not to a trace nutrient concept, but to a toxin-antitoxinhypothesis. Hopkins, who started his career as an analytical chemist, brought a chemical background into a medical environment when he became associated with Michael Foster's physiology laboratoryin Cambridge.Had Hopkins been given an opportunity to pursue his early thought on "accessoryfood factors," he might very well have opened up the whole vitamin development. Unfortunately, he was diverted into other directions by the necessities of laboratory studies and, while he made exceedingly acute observations im recognizing the role of trace nutrients, he himself was to play only a minor role in the history of vitamins. Funk, a Polish chemist trained in Germany and working at the Lister Institute at the time he enunciated the vitamin concept, was temperamentally unable to exploit the start which he had made on extracted materials from rice polishings and yeast. By overestimatingthe potency of his concentrates he ran into a period of stagnation which enabled others to bypass him. Thus, the nutrition breakthroughcame not from medical circles but from agriculturalcircles, not in Europe,but in the United States. 26

Conflictof Conceptsin EarlyVitamin Studies The rise of the agriculturalexperiment stations in the United States reflects a Germanheritage. Samuel W. Johnson was educated under Liebig at a time when he was highly interested in agricultural and physiological problems. On his return to the United States he was responsible to a significant degree for setting up the Connecticut Agricultural Experiment Station, and, in fact, was a spark in setting up the whole agricultural experiment station movement in the United States.67Passage of the Hatch Act in 1887 brought about the creation of agricultural experiment stations in most of the states of the Union. The early work in these experiment stations reflected the heritage of the German experiment station, with principal attention given to practical agricultural problems involving soil fertility, development of better strains of plants and aniimals, and comparison of the equivalency of feed materials. Animal feeding experimentswere carried out in large numbers in these stations but always with close attention to practical matters such as the value of one grain as a substitute for another in feeding for gain of weight or for milk production. Two stations, those in Connecticut and Wisconsin, stand out for a certain uniqueness which was to lead them to the recognition of the trace nutrientconcept. The Wisconsin station was probably even more representative of German traditions than the Connecticut station. During its first two decades this station directed an enormous amount of attention to the equivalencyof rations derivedfrom different plant sources. A number of times there was evidence of the significance of one food in supplementingthe value of another. This was particularly true of milk derivatives such as whey.68 While these results were not missed, they were never followed up in a systematic fashion; but there continued to be a tendency to accept the German feeding tables as being of primary value in the creationof rations for farm animals. When Stephen M. Babcockcame to the Wisconsin Station in 1888 he brought with him a skepticism regarding the signifi67. U. S. Dept. of Agriculture, Office of Expt. Stations, Expt. Sta. Record, 3 (1891-92), 1-5. C. E. Rosenberg presents some perceptive background to the origins of American agricultural experiment stations in his ardcle, "On the Study of American Biology and Medicine: Some Justifications," Bull. Hist. Med., 38 (1964), 364-376, and recognizes the role of agricultural chemists in opening up the vitamin problem. Also see Follis (fn. 36 above) on the failure of medical men to recognize the role of food; and S. L. Becker, fn. 4 above, pp. 25-36. 68. S. L. Becker, fn. 4 above, pp. 37-77, esp. 69-71.

27

AARON J. IHDE AND STANLEY L. BECKE

cance of feeding schemes based upon equivalencies reflected by chemical analyses of feeds. This skepticism led him into certain difficulties with his colleagues, particularly when he sought to test out his theories on valuable station animals.69 In 1907 three of his associates initiated a single-grainfeeding experiment using cattle as experimental animals. Four lots of heifer calves were fed "scientificallybalanced"rations derived entirely from parts of the wheat plant, the oat plant, or the corn plant, with a control group deriving its ration one-third from each of the test rations. It immediately became apparent that the wheat-fed animls were not adequatelynourished, and soon thereafter the oat-fed animals and the control animals began to show signs of dietary failure as well. Only the comfed aniimalsappearedto be properlynourished.70 Soon after the onset of the experiment it was decided that chemical analysis was necessary to find the cause of the deficiency in the wheat and oat diets. A young chemist, Elmer V. McCollum,was brought from Yale to undertake the necessary analytical work. Before more than a few months had passed, McCollum despaired of obtaining positive results on cattle and initiated feeding experiments using albino rats as test animals."' Concurrently,at the Connecticut station there had been less attention to animal feeding studies; instead, the principal activity had been in connection with proteins. Thomas Burr Osborne spent much of his professional career on the isolation, purification, and analysis of plant proteins. Osborne'ssuperb work on purification of plant proteins made available to him the finest protein material possessed anywhere for analysis. At this particular time the peptide hypothesis of protein structure was introducedby Emil Fischer, who also introducedthe ester fractionation procedure for analyzing proteins for amino acid content. Osbornebecame aware that, contraryto common belief, proteins varied significantly both in physical and chemical prop69. On Babcock and his activities see A. J. Ihde, "S. M. Babcock: Benevolent Skeptic," Proceedings of the Conference on History of Science and Technology held at the University of Oklahoma, April 1969, in press. 70. E. B. Hart, E. V. McCollum, H. Steenbock, and G. C. Humphrey, "Physiological Effect on Growth and Reproduction of Rations Balanced from Restricted Sources," Wis. Agric. Expt. Sta., Research Bull., no. 17 (1911).

71. E. V. McCollum, From Kansas Farm Boy to Scientist (Lawrence, Kansas, 1964), pp. 114-123.

28

Conflictof Conceptsin EarlyVitamin Studies erties-this being particularly evident in the distribution of amino acids. This had been shown to be the case thirty years earlier by Carl Heinrich Ritthausen72but only a few chemists, notably Albrecht Kossel, Emil Fischer, Hopkins, Babcock, and Osborne, took serious notice. Osborne'spainstaking isolation, purification, and analysis of plant proteins was an impressive sequel to the workof Ritthausen.73 It soon became apparent to Osborne that proteins vary a great deal in amino acid content, a protein like the zein of corn being totally devoid of certain amino acids which are present in animal proteins like casein. Osborne's colleague in New Haven, Lafayette B. Mendel, a physiological chemist at Yale, soon began questioning the comparativenutritive value of different proteins. The two men decided to carry out feeding studies to determine whether one protein might be substituted for another, and to learn whether certain amino acids were essential to animal nutrition. They began feeding rats on synthetic diets in 1909, shortly after McCollum began his ratfeeding studies at Wisconsin. Both groups of experimenters soon encountered great difficulties in creating a basic diet of synthetic foodstuffs that would provide for satisfactory growth and maintenance in the experimental animals. McCollumsought the answer to his difficulties in palatability, a point used by Voit two decades earlier to explain growth failure of animals on synthetic diets. He attempted to make his diets more attractive to rats by introduction of bacon fat, flavoring material, and so on. Osborne and Mendel found that their diets would maintain an animal if they contained a material which they called "protein-freemilk," essentially a lactose preparationcontaining traces of unknown impurities. However, continued studies over the next several years led to indifferent success in the creation of satisfactory basal diets. It was finally learned in 1913 that no diet was entirely satisfactory for growth unless a trace of butterfat was added along with the protein-free milk. McCollum and MargueriteDavis74 were the first to publish their recognition of the need for butterfat, although Osborne and Mendel75 had already come to 72. C. H. L. Ritthausen, Die Eiweisskrper deT Getreidearten Hulsenfruchte und Oelsamen (Bonn, 1872). 73. T. B. Osborne, The Plant Proteins (London, 1912). 74. E. V. McCollum and Marguerite Davis, "The Necessity of Certain Lipins in the Diet During Growth," J. Biol. Chem., 15 (1913), 167-175. 75. T. B. Osborne and L. B. Mendel, "The Influence of Butterfat on Growth," J. Biol. Chem., 16 (1913), 423-437.

29

AARON J. IHDE AND STANLEY L. BECKER

this conclusion by the time McCollum'spaper appeared.During the next two years it graduallybecame apparentto the several investigators that no diet can be adequate when it merely contains the grosser constituents of food in a high state of purity; there must be present in addition certain trace nutrients which are found in butterfat and in the aqueous portionof milk itself. McCollum was successful in pinpointing the site of the fatsoluble growth factor in the nonsaponifiablematter of butterfat by transferringthis portionof butterfat to olive oil, an oil which is worthless per se as a substitute for butterfat in the synthetic diet.7f McCollum was also able to show that a trace material

present in the aqueous portion of milk was adsorbedto lactose, even lactose of reagent grade purity. Thus, in 1916 he and Cornelia Kennedy proposed the introductionof the terms "fatsoluble A" and "water-solubleB" for the unknown growth factors present in miLkand essential for the adequate nutrition of rats. CONCLUSION There can be little doubt that recognition and understanding of the deficiency diseases was delayed as a result of having to compete with more attractive medical concepts, namely, the germ theory of disease and the knowledge that illness can be caused by toxic agents. Consequently,there was little momentum from the medical direction which resulted in research programswhich would open up the field. The necessary research was to come to some extent from chemists connected with medical programs, as was the case with Hopkins, Funk, and R. R. Williams, but primarily from chemists connected with agricultural experiment stations.77 76. E. V. McColluxmand M. Davis, "Observationson the Isolation of the Substance in Butterfat Which Exerts a Stimulating Effect on Growth," J. Biol. Chem., 19 (1914), 245-259. 77. Lafayette B. Mendel (1872-1935) is an enigma with respect to this generalization since he had associations with the medical school at Yale. Mendel's undergraduate education was primarily humanistic. He continued at Yale, undertaking graduate work in physiological chemistry in 1891, working under Chittenden in the Sheffield Scientific School. Upon receiving his Ph.D. in 1893 he remained in the laboratory as assistant. In 1895-96 he spent a year in Germany to carry on research in the physiological laboratories of Rudolf Heidenhain at Breslau and Eugen Baumann at Freiburg. He was made assistant professor of physiological chemistry in the Sheffield School in 1897 and full professor in 1903. In 1921 he was made Sterling Professor of Physiological Chemistry in Yale University with joint membership in the faculties of the medical and graduate schools as well as the Sheffield Scientific School. At that time,

30

Conflictof Conceptsin EarlyVitamin Studies In certain respects, they were unlikely prospects to open up a field of researchin the medical realm. As Rosenberghas pointed out, But these men were neither physiologicalchemists nor physicians. They were agricultural chemists, and their analyses of feeding stuffs and agricultural products was not motivated by a concern for physiological abstractions but was dictated and supportedby the economic needs and political power of agriculture. Equally important, their work was shaped by the dominant assumptions, and limited by the standard techniques, of German organic chemistry. For in the United States, as in Germany itself, agricultural chemistry was simply a specialized branch of organic chemistry. And no doctrine of German agricultural science was more sacrosanct than the assumption, held generally between the 1870's and 1900, that a diet balanced with a proper mixture of proteins, fats, carbohydrates,and inorganic salts would, irrespectiveof the source of protein, provide a sufficient diet for men or animals.78 Thus, the progress of chemists on the deficiency disease problem was also delayed by adherence to concepts out of the past-the Liebig-Voitdoctrine of nutritional equivalencies of energy-producingfoods and of proteins, as well as the notion that minerals must come from organic combinations. Analysis for proximate principles served further to cover up the need to ask questionsaboutthe role of specificcompounds. Chemists were further handicapped by their own shortcomings. Again, to quoteRosenberg: Chemists performed surprisingly few experiments with animals, while medical men and physiologists seldom received highly specialized chemical training. Certainlybiologists and medical men had not accepted the assumption-natural to the chemist-that research should if possible be conducted with substances of known chemical composition and structure. Chemists, on the other hand, were relatively unfamniliar

with the technique of using experimental animals to test the physiological activity of known chemical substances or to differentiate closely related compounds. As a group, how-

a reorganization at Yale University brought the laboratory of physiological chemistry into the medical school. The experimental work on which his papers with Osbome are based was all done at the agricultural experiment station. See R. H. Chittenden, "Lafayette B. Mendel," Biog. Memoirs, Natl. Acad. Science8, 18 (1938), 123-155.

78. C. E. Rosenberg,fn. 67, pp. 370-371.

31

AARON J. IHDE AND STANLEY L. BECKER

ever, chemists were comparatively unacquainted with the literatureof clinical medicine.79 The agriculturalchemist's backgroundin animal feeding experimentsprior to 1909 was largely empiricaland was restricted to work with large farm animals. Because of their intrinsic value and the cost of feeding and maintenance, experiments on

such animals were restricted to small numbers, frequently a single animal. Further, growth is slow, reproduction is delayed,

and the life span is long, so results were accumulated slowly. Nevertheless, there was a reluctance in agriculturalcircles to shift to small, short-lived experimental animals until McCollum initiated the break in 1908.80

Chemically trained investigators were seriously handicapped in interpreting the results of their feeding experiments since they had had no experience in dealing with pathological symptoms in animals. This handicap existed for an extended period as nutritional work spread in the agricultural schools of the country. Fortunately, in the early work the diets were sufficiently bad that gross deficiencies and growth failure were clearly evident. It is strange that the real breakthroughoccurred in connectionwith the vitamin A deficiency,since this deficiency had not been clearly identified with human or animal diseases. It was lack of this factor, however, which revealed itself most clearly in poor growth and, in the work of Osborneand Mendel, in sore eyes.

Possibly it was fortunate that the pioneering work on vitamins was done not by physicians close to human diseases nor by physiologists familiar with anal experimentation,but by chemists who, although ignorant of such problems,were driven by directors concemed about the greatest output for the least input. Such investigators were in a position where current medical paradigms had little influence on them. While they were handicapped by the shortcomings of their own chemical paradigms, they were, in the face of conflicting evidence (with respect to identity of proteins, for example), able to rise above their biases and fumble toward the recognition of an organic trace nutrientconceptof deficiencydiseases. 79. Ibid., p. 371.

80. For the reaction of a college dean to the proposal that taxpayer's money be used to feed rats see E. V. McCollum, From Kansas Farm Boy to Scientist (Lawrence, Kansas, 1964), pp. 117-118. Also see A. J. Ihde, "The Basic Sciences in Wisconsin," Trans. Wis. Acad. Sciences, Arts, Letters, 54A (1965), 33-41. H. B. Vickery has told AJI that the Connecticut Station made no reference to its rat-feeding experiments in its reports to farmers during the early period.

32

Conflictof Conceptsin EarlyVitamin Studies Acknowledgment

We wish to thank the National Science Foundation and the University of Wisconsin Graduate School for support of this study. Parts of this paper were presented by AJI at a history of science colloquium, Yale University, March 2, 1967; at the Symposium on The History of Biochemistrysponsoredby the American Chemical Society, Chicago, Illinois, September 12, 1967; at a history and philosophy of science colloquium at the University of Toronto, Oct. 28, 1969; and at the Conference on Historyof Biochemistryand MolecularBiology, AmericanAcademy of Arts and Sciences, Brookline,Mass., May22, 1970. The present address of Stanley L. Becker is Bethany College, Bethany,West Virginia26032.

33

The Backgroundto EduardBuchner'sDiscovery of Cell-FreeFermentation ROBERT KOHLER

Burndy Library, Norwalk, Connecticut

INTRODUCTION: THE IMPORTANCEOF ZYMASE FOR BIOCHEMISTRY Eduard Buchner's discovery of cell-free fermentation in 1897 has long been celebrated as the resolution of one of the most famous scientific controversies of the nineteenth century, the controversy between Pasteur and Liebig over the nature of alcoholic fermentation. Was fermentation, as Pasteur contended, a vital physiological act of the living yeast cell, or was it due as Liebig claimed, to some purely chemical agent within the yeast cell? Could fermentation be separated from intact living yeast? Buchner showed that in a sense both sides were right: fermentation is carried out by soluble enzymes in yeast juice free of whole cells; but these enzymes are made by the living yeast cell. Buchner's work has also been long recognized as one of the most important foundations of the new science of biochemistry, which emerged in the early years of this century. The common ground of the small group of physiologists, chemists, and microbiologists who began to think of themselves as biochemists was the belief that all the physiological functions of the living cell would turn out to be mediated by enzymes. In time this idea became the "central dogma" of biochemistry. In 1897, however, it was highly subversive. Since the 1860's, when the protoplasm theories of cell structure and function made a clean sweep of cell biology" it had been universally assumed that the protoplasm as a whole carried out such essential functions as fermentation, respiration, and assimilation. Since only intact 1. T. S. Hall, Ideas of Life and Matter, 2 vols. (Chicago, 1969), esp. chaps. 42,47, and 49. Journal of the History of Biology, vol. 4, no. 1 (Spring 1971), pp. 35-61.

35

ROBERT KOHLER

living cells were known to carry out these complex chemical changes, it was perfectly natural to suppose that the protoplasm as a whole was the irreducibleunit of life. The soluble enzymes had of course been known for a long time, and by 1897 enzymologywas a well-establishedspecialty with a rapidly growing following. But enzymology before the 1890's was strictly limited in scope. For one thing, all known enzymes carried out only one simple chemical reaction-hydrolysis-and it was implicitly assumed that all enzymes would prove to be only hydrolytic agents. Respiration,fermentation, and synthesis, all these vital functions of life, were far too complex to be ascribed to enzymes. Moreover,all known enzymes were exo-enzymes, enzymes secreted by cells to function outside the cell. W. Kuhne,who coimedthe word "enzyme"in 1876, explicitly included in his definition that enzymes were exocellular agents.2 Thus, to ascribe the vital chemical changes of living cells to the action of enzymes would not only have been pure hypothesis, it would almost have been a contradictionin terms. The discovery of zymase broke through the bounds of nineteenth-centuryenzymology. Buchner'smethod of breaking cells by grinding with sand and then pressing out the cell juices with a hydraulic press led to a vast increase in the number of known endo-enzymes, and it was to zymase that biochemists most often pointed as evidence that the whole protoplasmwas not requiredfor even the most complex metabolic activities, but only the soluble enzymes in the cell juice. Zymase became a cause c6lebre; it dramatically reawakened the old debate on fermentation, and it brought the general issue of enzyme vs. protoplasm to a head. There were reports that Buchner's experiments could not be confirmed; protoplasmists claimed Buchner was working with large pieces of surviving protoplasm. But in the ensuing debate the protoplasmistswere forced to retreat, and the view that zymase was an enzyme (or enzymes) became generally accepted. Understandably,the discovery of zymase came to be regarded as putting an end to the nineteenth-centurybiology of the cell and protoplasm,and as the beginning of the new chemical biology of the twentieth century. Every new science needs its historical mythology, and zymase is both satisfying and in many ways historically accurate. In one way, however, this view is misleading. In fact, there 2. W. Kiihne, Verhandi, Nautrhist.-Med. Ver. Heidelberg, 1 (1877), 190-193. Meeting of February4, 1876.

36

Eduard Buchner's Discovery of Cell-Free Fermentation was no real continuity between the earlier controversies over fermentation and Buchner's discovery. For about twenty years before 1897 the controversy between the vital and chemical theories had been dormant. Moreover, Buchner himself was not working on fermentation at the time he discovered zymase. His discovery grew by accident out of a different though related field of immunochemistry. By 1897 immunology had achieved striking success in giving chemical-physiological explanations of disease and immunity, while the study of fermentation was relatively backward. The new science of biochemistry, with its central concern with the intracellular enzymes of microorganisms, took a great deal from the more sophisticated medical microbiology. In short, to see the discovery of zymase as a culmination of the fermentation tradition of Liebig and Pasteur is to miss one of the most important elements which went into the new science of biochemistry and one of the most important Teal threads of continuity between nineteenth- and twentieth-century biology. THE CONTROVERSYOVER FERMENTATION, 1838-1878 Until 1837 fermentation had been regarded as a purely chemical process: the spontaneous decomposition of an unstable chemical ferment transmitted its "vibrations" to sugar molecules, which broke down to alcohol and carbon dioxide. In 1837-38 it was proposed independently by Charles CagniardLatour (1777-1859),3 Friedrich Kutzing (1807-1893),4 and Theodor Schwann (l810-1882)5 that fermentation was a vital activity of living yeast cells. According to Schwann, sugar was consumed by the yeast, and alcohol and carbon dioxide were excreted. In 1839 Justus Liebig reaffirmed the chemical theory in a typically intolerant attack on the "vitalistic" theory: any living yeasts found after fermentation were the result not the cause of fermentation. The issue was a lively one in the 1840's and soon became quite complex.8 In theory, however, there was a simple experimental solution. If active "ferment" was really living yeast, then mechanical destruction of the cells should destroy their ability to ferment, whereas the activity of a chemical ferment should not be impaired by mechanical grinding. In 1846 this crucial experiment was carried out by F. W. Ludersdorff, who ground yeast be3. 4. 5. 6.

A. Cagniard Latour, Ann. Chim., 68 (1838), 206-222. F. Kiitzing, J. Prakt. Chem. (II), 1837, 385-409. T. Schwann, Ann. Physik, 41 (1837), 184-193. See, for example, H. Helholtz, J. Prakt. Chem., 31 (1844), 429-437.

37

ROBERT KOHTE

tween ground-glass plates.7 The crushed yeast cells produced not one bubble of carbon dioxide. However,with an experiment of this sort, only a positive result is really meaningful, and Liidersdorffdrew no conclusion. C. Schmidt, a student and disciple of Liebig, repeated the experiment but concluded that fermentation was due to a purely chemical 'Bewegung."8 By 1850 Liebig's chemical theory was widely prevalent,9 and if the vitalist theory was never ruled out, the issue at least ceased to be an activelydebatedone. In 1860 the tables were turned by Pasteur's well-knownexperimnentson fermentation, which demonstrated that fermentation required the presence of living yeast cells.10 Pasteur conceived of fermentation as "anaerobicrespiration,"whereby the yeast used the oxygen from one part of the sugar molecule to oxidize the carbon of the other part, thus permitting life in the absence of air. Pasteur's conception of fermentation as a physiological act, backed up by his exhaustive experiments, dominated the 1860's as completely as Liebig'schemical theory had the decadebefore. For some, however, calling fermentation a physiological act still left room for deeper physiological questions about the cause of fermentation.In 1860 MarcelinBerthelot (1827-1907) suggested that fermentation was the result of the action of intracellular ferment,1' but failed to extract a fermentation enzyme from yeast by maceration. An elaborateenzyme theory of fermentation had been proposedtwo years earlier by Moritz Traube,'2a remarkableand gifted man, who had begun studies in medicine and physiological chemistry but had been obliged to take over the family wine business on the death of his older brother.'3 His limited researches on fermentation, osmosis, and respiration showed his obvious gifts. Though Traube'senzyme theory of fermentation was far more plausible than Liebig's naive chemical ferments, neither Traube nor Berthelot was much heeded in the general success of Pasteur's "life without air." In 1870 the debate was reopened by a rambling attack by Liebig, now 70 years old, on Pasteur'sexperimentalevidence.14 7. F. W. Liidersdorff, Ann. Physik, 67 (1846), 408-411. 8. C. Schmidt, Ann. Chem., 61 (1847), 168-174. 9. A. Harden, Alcoholic Fermentation (London, 1910), chap. 1. 10. L. Pasteur, Ann. Chim., 58 (1860), 323-426. 11. M. Berthelot, Compt. Rend. Acad. Sci., 50 (1860), 980-984. 12. M. Traube, Theorie der Fermentwirkungen (Berlin, 1858), and Ann. Physik, 103, 331-344. 13. G. Bodlander, Ber. deut. chem. Ges., 28 (1895), 1085-1108. 14. J. Liebig, Ann. Chem., 153 (1870), 1-47.

38

Eduard Buchner's Discovery of Cell-Free Fermentation Liebig had by then more or less come around to the view that "ferment" was an enzyme, not a decomposing protein. But he clung to enough of his older outmoded view to make him a sitting duck, and in 1872 Pasteur published a brief and devastating rebuttal,'5 to which Liebig never replied and which, according to legend, hastened his way to the grave. The debate continued throughout the 1870's between Pasteur and Felix Hoppe-Seyler (1825-1893), the leading physiological chemist of the day, and champion of the enzyme theory.'8 Traube claimed priority for the enzyme theory and criticized HoppeSeyler, and the three-way debate that ensued soon became entangled in details. During the 1870's several more attempts were made to isolate an active ferment free of intact yeast cells.17 Marie Mannesein, a student of the botanist Julius Wiesner in Vienna, carried out a long series of experiments in 1870-71 on yeast killed by heat of up to 300 degrees, which allegedly could still carry out fermentation.'8 In a single experiment she tried Liidersdorff's mechanical method of breaking cells. Yeast was ground with quartz powder for 15 hours "by a strong man," and the resulting paste after seven days' incubation with sugar water gave a fine yield of alcohol-and a fine crop of yeast. Grinding was much less efficient than charring in kiling yeast, and Mrs. Mannesein did not repeat the experiment. (However, she remained firmly convinced that fermentation was caused by a chemical ferment.) About 1878 Pasteur himself tried to isolate "alcoholase" from yeast, as Emile Roux recalled some twenty years later: Mr. Denys Cochin did preliminary investigations in Pasteur's laboratory, which came to nothing. Pasteur himself undertook experiments on the subject, and I remember that at the time I came to his laboratory [c. 1878] he was trying to extract soluble alcoholic ferment from yeast cells by grinding in a mortar, by hammering frozen cells, or again by placing them in concentrated salt solution to force the sugar by osmosis to the outside of the cell envelope. All in vain. Pasteur did not find alcoholase. If he did think its existence conceivable, he did not think it was a reality.'9 15. L. Pasteur, Ann. Chim., 25 (1872), 145-150. 16. F. Hoppe-Seyler, Arch. Ges. Physiol., 12 (1876), 1-17. 17. M. Teich, Acta historiae rerum naturalium necnon technicarum, special issue 2 (Prague 1966), pp. 69-74. 18. M. Mannesein, in J. Wiesner, Mikroshopische Untersuchungen (Stuttgart, 1872), pp. 116-128. 19. E. Roux, Annales de la brasserie et de la distillerie, 1 (1898), 512.

39

ROBERT KOHLER

Pasteur probably believed that alcoholase did not exist, but was certainly aware that a negative result was no proof; he never publishedhis results. The final scene in the controversywas precipitatedby Berthelot's publication in 1878 of some notes found among the Nachlass of Claude Bernard, in which the great physiologist confided his belief that his friend Pasteur was wrong and that fermentation was due to an intracellular enzyme.20Pasteur replied to Bernard's doubts and few tentative experiments with a barrage of letters to the Comptes rendues and a series of dramatic public demonstrationswhich appeared as a book in 1879.21After this administrationof the club of reason and scientific method, the issue ceased to be an active one, and it remained so until it was revived by Buchner in 1897. Many experiments were done on the role of oxygen in fermentation and other vexed questions raised by Pasteur's work, but no effort was made to test the enzyme hypothesis itself. The issue was not debated, and there are no recorded attempts to break open yeast cells by mechanical means. Nageli and Loew were probably expressing the general view when they flatly stated in 1878 that the protoplasmiccontents of yeast cells could not be releasedby mechanicalmeans.22 Thus, for nearly twenty years before 1897, the existence of an alcoholase was not an active scientific problem, and twenty years is a long time in a science as active as cell biology. How then was the thread picked up again by Buchner twenty years later? Cell-free fermentation was first observed in yeast extracts preparedby Eduard'sbrotherHans Buchner, the immunologist, to test a new method of getting proteins from bacteria for immunization. Unlike the fermentation tradition, the germ theory of disease and immunity had enjoyed a period of tremendous expansion from 1880 on, and beginning about 1890 was undergoing a radical development from a cellular to a chemical-physiologicalscience. The discovery of zymase was a result of this new approachto medical science, and it in tum stimulated similar revolutionary changes in the biochemical study of cell life. Quoted in E. Buchner et al., Die Zymase (Munich, 1903), p. 13. A somewhat different version is reported in Schweiz. apotheker Ztg. 37 (1898), 54-57. See also D. Cochin, Ann. Chim., 21 (1880), 430-432. 20. C. Bernard, Rev. Sci., 22 (1878), 49-56. 21. L. Pasteur, Examen critique d'un ecrit posthume de Claude Bernard sur la fermentation (Paris, 1879). 22. C. Nageli and 0. Loew, Ann. Chem., 193 (1878), 322-348; esp. p. 322.

40

Eduard Buchner's Discovery of Cell-Free Fermentation THE GERM THEORY OF DISEASE AND IMMUNITY For nearly fifty years the germ theory of disease and the cell theory of fermentation ran a parallel course. Jacob Henle whose Pathologische Untersuchungen of 1840 (1809-1895), prefigured the germ theory of disease, was a friend of Schwann and cited as evidence for his views Schwann's work on fermentation.23 The cell theory of fermentation was a hopeful precedent for the search for parasites in connection with contagions, a search that became more intense during the 1850's.24 Pasteur's interest in the germ theory of disease likewise grew from his success in dealing with fermentations. Pasteur had found that each kind of chemical fermentation-alcoholic, butyric, acetic, etc.-was caused by one special kind of microorganism, distinctive in morphology and nutritional needs. So too with the various "diseases" of wine and vinegar, and so too Pasteur was convinced would be the case with the various diseases of the human body. During the 1870's and 1880's this expectation was amply fulfilled, and the germ theory of disease became as firmly ensconced as the ruling dogma in medical science as the germ theory of fermentation was in that field. There were also counter arguments analogous to those of Liebig and Hoppe-Seyler, that chemical toxins and ferments were the causes of disease. These toxic nitrogenous end products of bacterial metabolism were thought to be responsible for the symptoms of diseases such as pyemia or septicemia, as they were for the similar signs of decay in putrifying meat broth. Various chemical theories of disease were quite popular in the 1850's, and the analogy with Liebig's theory of fermentation was often quite explicit. For example, in 1855-56 C. Thiersch (1822-1895), likened the virulent cholera dejecta to Liebig's ferments. The decomposition of these compounds, he believed, induced the decomposition of the living tissues.25 Weber came to the same conclusion in 1864, but was uncertain whether the putrefying ferment was corporeal or humoral-that is, organized or simply chemical. Bacteria, he believed, were not involved. Pasteur's demonstration that putrefactions too were caused by specific bacilli convinced most workers that septicemia was not the result of a metabolic disorder but of an invasion of a parasite. But the chemical tradition continued to be upheld, frequently by such men as Hiller and Pavitch, who opposed 23. W. Bulloch, The History of Bacteriology (Oxford, 1960), pp. 163-165. 24. Ibid., pp. 165-168. 25. Ibid., pp. 131-135.

41

ROBERT KOHLER

the germ theory of disease. They wanted a physicochemical theory as a counterweightto the prevailing vitalist dogma. For the same reason that Liebig's advocacy sealed the fate of the enzyme theory of fermentation, the association of the chemical theory of disease with reactionary refusal to accept any part of the new germ theory helped to put the physicochemical approachto the physiology of disease in the shade. The failure to find any lethal toxins in cases of fatal infections likewise dampened enthusiasm for the chemical theory. The persistent investigations by L. Brieger (1849-1919) of alkaloid-likeptomaines produced in bacterial infections kept the chemical tradition alive, but Brieger's work was decidedly a dissident strain, at least until the 1890's. The much-celebrateddescription by Robert Koch of the anthrax bacillus (1876), and the dramaticisolation of the bacilli causing cholera, typhus, plague, etc., insured the domination of the germ theory. Throughout the 1880's the order of the day was to isolate and characterize specific pathogens. The challenge was great enough, and the opportunitiesfor reward rich enough, so that there was little need to ask deeper questions as to the physiology of disease. In the field of immunity, too, the cell theory prevailed, though more slowly than the germ theory of disease. Pasteur's work on immunity was exclusively empirical and practical, and the first theory of immunity was Elie Metchnikoff's(18451916) theory of phagocytosis,26proposed in 1884. Unlike fermentation, phagocytosis was a process that could be witnessed under the microscope, and phagocyte cells devouring whole bacilli was demonstrablya physiological act of the whole cell. Metchnikoffs theory was slow to win acceptance during the 1880's, though it was the only candidatein the field. By the time it became widely acceptedin the early 1890's profoundchanges were occurring in the theory of disease and immunity, and there was another, chemical theory of immunity to contend with. This chemical theory was championed by, among others, Hans Buchner, older brother of the discoverer of zymase and one of the principalsof this piece. HANS BUCHNERAND THE RISE OF IMMUNOCHEMISTRY, 1875-1893 Hans Buchner (1850-1902) was born on December 16, 1950, into an old Munich professionalfamily, grandsonof a Bavarian minister and son of a medical jurist and physician.27He studied 26. Ibid., pp. 259ff. 27. F. Hueppe, Mfinch. Med. Wochschr., 49 (1902), 844-847.

42

Eduard Buchner's Discovery of Cell-Free Fermentation medicine with Carl Ludwig (1816-1895) at Leipzig and in 1875 became a regimental physician, rising eventually to the position of surgeon-general. In 1880 he began an academic career by habilitating at Pettenkoffer's Institute of Hygiene at Munich, where in 1892 he became professor extraordinary, and in 1894 he succeeded Pettenkoffer to one of the most prestigious chairs in Germany. His successful career was cut short by his death in 1902 of an intestinal cancer. He was an imposing figure and a man of considerable distinction in his day. The most important influence on Buchner's scientific work was his exposure to the fertile and wide-ranging ideas of the botanist, Carl W. Niigeli (1817-1891), professor and director of the Plant Physiological Institute at Munich. Buchner studied with Naigeli in the late 1870's and performed his first scientific researches trying to prove Niigeli's conviction that there were no fixed bacterial species. Buchner claimed to have found that anthrax bacilli could be reversibly transformed into hay bacilli by 1000 serial cultures. It was just at this time that Koch's work on the life cycle of anthrax appeared, and Naigeli and Buchner definitely got the worst of the controversy that ensued with Koch.28 Whether Buchner had observed an attenuated form of anthrax which looked like B. subtilis, as his biographer claimed, or whether he was the victim of contamination, as his opponents claimed, is not really important. At the time, Buchner was saddled with the reputation of having been exposed in an embarrassing experimental error, a reputation he never entirely lived down. (At least his biographer still felt obliged to defend him in 1902.) This episode was the first of several in which Buchner found himself defending a less and less tenable opinion and gradually had to give way to criticism. Despite his worldly success, Buchner was unwise or unlucky in his choice of scientific causes, and that aura went with his name into the history books.29 The germ of what was to be Buchner's most important work was likewise inherited from Niigeli in the late 1870's. In 1877, in his Mikroskopische Untersuchungen, Niigeli set forth the theory that infectious diseases were caused by bacterial parasites, which by using up the best nutrients and by excreting toxic substances caused the symptoms of disease. But if the body was simply a rich culture medium for bacilli, Nageli asked, why did every stray invader not inevitably kill the host? The reason must be that the animal organism had defenses of its 28. W. Bulloch, History of Bacteriology, pp. 200ff. 29. See Bulloch's rather unfair estimate of Buchner's work, ibid., pp. 258-259, 271-272.

43

ROBERT KOHLER

own and engaged with parasites in a Kampf ums Dasein, a struggle for survival analagous to the Darwinian struggle for survival between species. What these defensive weapons were Nageli could not say. Medical science in 1877 had little knowledge of the physiology of disease, and Nageli was not even a medical man.30

Hans Buchner was deeply impressed by Nageli's conception of disease as a Kampf ums Dasein.31He also believed he had identified the body's specific defense agaist invasion: namely, inflammation and suppuration.82If inflammation was not a pathological symptom, as was usually believed, but a sign of health and resistance to disease, then any artificial means of stimulating inflammation would be a valuable therapeutic aid to the organism in its battle for existence. Buchner believed that arsenic was the most effective therapeutic,and so strongly convinced was he that he took a leave of absence in 1883 to try it out in the field; with how much success is not clear. In any case, Buchner'senthusiasm for his theory of inflammation was a lasting one, despite the lack of proof. In 1888 Buchner unexpectedly obtained definite experimental evidence that inflammation was indeed antibacterial.83He developed an apparatusfor causing animals to breathe a dried dust of anthrax spores and cells (not an uncommon experiment at the time). He observed that this dust caused two distinct stages of disease in the lungs: first, pneumonia, and then infection by anthrax itself. On microscopic examination of the lungs at the pneumonial stage, Buchner observed that the central mass of inflamed tissue was filled with broken and degenerated anthrax cells. Around the periphery of the inflammation, in contrast, active threads of anthrax were to be seen growig and penetrating the lung tissues. It was obvious what was going on. The anthrax bacilli somehow caused inflammation, and the inflammation in tum killed the invading bacilli, thus hindering their spread.34Unfortunatelythe anthrax on the periphery usually outran the inflammation and killed the animal. Here was Nageli's Kampf ums Dasein in progress, visible on the microscopeslide. But what was the actual physi30. Hans Buchner, Munch. Med. Wochschr., 38 (1891), 435ff. 31. ihren 32. 33.

H. Buchner, Die Nagelische Theorie der Infektionskrankheiten in Beziehungen zur medizinische Erfahnsng (Leipzig, 1877). F. Hueppe, Munch. Med. Wochschr., 49 (1902), 845. H. Buchner, Munch. Med. Wochschr., 36 (1889), 22-25, 42-45.

Lecture to the Munich Society of Physicians, November 21, 1888. 34. Ibid., 25.

44

Eduard Buchner's Discovery of Cell-Free Fermentation ological cause of inflammation and its lethal effect on bacteria? That was Buchner's question. Phagocytosis was certainly involved: invading bacteria attracted phagocytes and were devoured in the battle for existence.35 But not long before, evidence had suggested the existence of more sophisticated chemical defenses that operated outside the cells of the animal organism.36 For example, J. Fodor and G. H. F. Nuttall had noticed in 1887 that blood from an animal immunized to anthrax hindered the growth of anthrax bacilli; similarly, R. Emmerich and diMattei found that killing of anthrax by immune blood was far too rapid to be explained by phagocytosis.37 Needless to say, Buchner saw these novel facts as a vindication of Nageli's old prediction that the body tissues themselves were active in the struggle for survival, and he immediately began investigations himself. With Friederich Voit he found that the blood of nonimmunized animals also hindered the growth of anthrax.38 Most important, they discovered that the antibacterial agent was present only in fresh "living" serum, and that it was destroyed by heating to 55 degrees, exactly as enzymes were. Emmerich believed that the active agent was a chemical toxic to bacteria, an opinion which came from the chemical tradition of Brieger. Buchner concluded on the contrary, that the active agent was the living protein of the blood plasma itself, as Nageli might have predicted: We may tentatively assume that it is the chemical properties of the living blood plasma, in this case the true blood serum, that is harmful to bacteria. I do not know how that comes about, but I do know there are grounds for believing that living protein is chemically different from dead protein.39 The belief in a special "living" protein, as chemically distinct from "dead" protein such as egg albumin, was quite a common idea in the late nineteenth century, especially among physiologists. Since cell protoplasm was known to consist mainly of protein and was believed to be the special machinery of life functions, it was natural to assume that a special active, living protein was involved. (Enzymes were also thought to be 35. Ibid., 42. 36. Ibid., 43, ". . . beim hoher entwickelten Organismus uiben gewisse Zellen in atavistischer Weise eine phagocytare Thatigkeit; ausserdem aber haben sich im Laufe der hoheren Entwicklung nebenher noch andere physiologisch-chemische Einrichtungen ausgebildet, die auf eine zweckmdssige BekAmpfung der Infectionszufuhr gerichtet sind." 37. Ibid., 43. 38. Ibid. 39. Ibid., 44.

45

R0BERT KOHLER

active proteins, though they were seldom thought to be 'living" ones.) EduardPfliiger (1829-1910), the noted physiologist,was a staunch believer in the chemical-protoplasmtheory, and his student, Oscar Loew (1844-1941), was the originator and detennined advocate of a theory of how living and dead protein differed in chemical structure.40It was undoubtedly Loew's extensive workthat Buchnerhad in mind. It is important to note the tradition from which Buchner drew his idea of active blood serum. It was not the purely chemical tradition of the antigerm theorists, nor the pure cell theory of Pasteur and Metchnikoff, though Buchner was a vocal supporter of Metchnikoff's work. It was the tradition which encompassedboth the theonresof protoplasmand "giant living molecules"that camredout all the functions of life, and the physicochemicalviews of active proteins and enzymes. This emerging tradition included the chemically minded physiologists and the chemists with interests in physiology. It was in this indefinite no man's land between two sciences that zymase and biochemistryeventually were established. The antibacterialproteins of blood, or "alexines"as Buchner named them in 1891,41 were Buchner's maI concern for the rest of his career, and a chronic source of controversy.Buchner was soon engaged in a running debate with Metchnikoff,who felt his cellular theory threatened by the new chemical or "humoral"theory of immunity, as he called it, harking back to the discreditedpre-germ"humoral"theories of disease. The debate over where bacteria were destroyed, inside or outside the phagocytes, was complex, protracted, and often at cross-purposes, and we need pursue it no further here except to note that in the eyes of his contemporariesHans Buchner fought a losing battle.

Buchner's ideas about inflammation also involved him in the second major developmentin the new immunochemistryof the early 1890's, namely, the dramatic discovery of antitoxins and serum therapy. It was this involvement that led indirectly to the discovery of zymase. In 1888 C. E. Chamberland(18511908) and Emile Roux (1853-1933) in the Pasteur Institute noted that immunization could be carried out by heat-sterilized suspensions of anthrax bacilli and their culture broth, which contained the toxic products excreted by the living cells.42 This observationwas quickly developedby Emil Behring (185440. See, e.g., 0. Loew and T. Bokorny, Ber. deut. chem. Ges., 14 (1881), 2589, and subsequent papers. For a bibilography see M. Klinkowski, ibid. 74A (1941), 115-136. 41. H. Buchner, Mfinch. Med. Wochschr., 38 (1891), 435-437. 42. Ibid., 36 (1889), 22-24.

46

Eduard Buchner's Discovery of Cell-Free Fermentation 1917) and S. Kitasato (1852-1931) of Koch's Institute im Berlin into a successful method of immunization for tetanus and diphtheria, the symptoms of which were caused by specific protein nerve toxins excreted by the bacilli. Behring and Kitasato also observed the remarkable fact that immunity was conferred not only against live bacilli but against their toxic secretions as well. The cell-free serum from immunized animals could even be used to treat animals already infected with diphtheria and tetanus: something in the immune serum neutralized or destroyed the highly specific protein toxins already present. Behring's discovery of these "antitoxins," as he proposed to call them, astounded the medical world, and throughout the 1890's serum therapy had a tremendous vogue. Hans Buchner's interest was less in the practical than in the theoretical significance of serum therapy, which he recognized as yet another vindication of Nageli's prophetic vision. Roux had explained immunization by heat-killed cultures by analogy with the bacterial growth cycle: just as the poisonous excretion products of bacterial metabolism accumulated in a broth culture and eventually stopped further growth, so they should do the same when injected into the blood stream of a living animal. Buchner pointed out that if Roux were right, Roux's treatment should be therapeutic, when in fact it was only prophylactic. It was not merely a chemical effect but true physiological immunity that Roux observed. Buchner observed that far too much significance had been given to the chemical "decomposition products" of bacteria, to which all pathological effects had been ascribed. The answer to the mechanism of immunity lay in the chemistry and physiology of the cell itself.43 Again we see Buchner rejecting the simplistic chemical explanation for the difficult middle ground of chemical physiology. And again his experiments with inflammation soon indicated the importance of intracellular proteins-in this case, bacterial proteins. Early in 1890 Hans Buchner reported to the Munich Society for Morphology and Physiology that bacterial intracellular proteins alone could cause inflammation. For example, pneumococci sterilized at 120 degrees caused inflammation when injected under the skin of an animal.44 Since culture filtrates had no such effect, the active substance must be intracellular, and was probably protein of the protoplasm. This result fitted neatly into Buchner's conception of inflammation: It must be assumed that when pathogenic bacteria are destroyed in living tissues, and they are destroyed in large 43. Ibid., 23.

44. Ibid., 37 (1890), 510-511. Read May 6, 1890.

47

ROBERT KOHLER

numbers in many infections, simultaneouslywith their multiplication-substances from the bacterial cell are spilled out and are responsible in large part for the inflammation and fever produced.45 The significance of the broken anthrax cells in his earlier experimentswas now clear. In July 1890 Buchner reportedto the same society new evidence for his view. He isolated the protoplasmicprotein from pneumococcus by extraction with dilute alkali and precipitation with acid.46This method was discovered a decade earlier by Marcel Nencki (1847-1901),47 a Polish physiological chemist, who had also predicted that the intracellular proteins of specific pathogens would be responsible for the specific symptoms of diseases.48Buchner found that this protein alone was not very active; but placed in a glass capillary and inserted under the skin on an animal it caused inflammation and the formation of pus-all without the appearance of a single live bacfllus. Even the dead protoplasmicprotein, partly inactivated by the extraction, could evoke the defensive mechanisms of the host: 'Vhereas before only the living bacterial cell with its chemical activities going could be considered in explanations of pathogenesis, we must now take into considerationthe contents of the degenerating cell."49 Buchner was again treading the narrow line between chemistry and physiology, between dead protein and living protoplasm, toward the new biochemistry of the cell. Evidence for Buchner's theory continued to appear. In the fall of 1890 Buchner reported that proteins from a variety of pathogens were strong chemotactic attractants for leucocytes, whereas a variety of "ptomaines"and bacterial decomposition products such as amino acids, fatty acids, alkaloids, to which inflammation had traditionallybeen ascribed, had no effect.50 Grist for Buchner's mill also came from Koch's dramatic announcement of "tuberculin"in the fall of 1890, and the tremendous public acclaim it received.51Tuberculinis a preparation of tubercle bacilli, which when applied to tubercular 45. Ibid., 510. 46. Ibid., 510-511. Read July 8, 1890. 47. M. Hahn, Ber. deut. chem. Ges., 35 (1902), 4503-4521. 48. M. Nencki and F. Schaffer, J. prakt. Chem., 20 (1879), 443-466. M. Nencki, Ber. deut. chem. Ges., 17 (1884), 2606-2608. 49. H. Buchner, 511. 50. H. Buchner, Munch. Med. Wochschr., 37 (1890), 842-843. Read to the Morphological Society November 11, 1890. 51. See H. Buchner, Munch. Med. Wochschr., 37 (1890), 832-834.

48

Eduard Buchner's Discovery of Cell-Free Fermentation lesions of the skin leads to a vigorous reaction; the diseased tissues grow inflamed and necrotic and fall away, and the bacilli are killed. Koch did not say how he made his preparation, but Buchner guessed that it must be specific bacterial protein: I think I have a right to assert that tuberculin is nothing but the protein-like constituents of the plasmatic cell contents, the so-called proteins, or perhaps if it should be a single substance, the "protein of the tubercle bacillus." 52 The reaction which Koch saw as necrosis, Buchner recognized as inflammation. Acclaiming his old adversary's great practical achievement, Buchner laid claim to the theory which explained its success, a theory he had been pressing on an uninterested world for ten years. Buchner's historical view of the new chemical physiology of disease appears in a most interesting lecture of June 1891 on "Bacteriology since Nageli," in honor of his teacher's recent death.53 Buchner claimed for Nageli's parasite theory the honor of its being the first step toward a true physiology of disease, which was only then beginning to emerge from the orthodoxy of Pasteur and Koch: Finally people are becoming aware that the discovery of a pathogen-the cause of an infectious disease in the popular phrase-in no way exhausts the true scientific interest. The questions of how and why are being met with more and more from all sides.54 Quoting Virchow's complaint that the "poor little cells" have been badly neglected while everyone gaped at colored microbes, Buchner agreed that the cell itself was again coming into its own: Gradually the movement is growing toward a deeper understanding, toward a physiological theory of the infectous process and . . . its opposite, what is called immunity or the healing process.55 The foundation of this new physiology of infection and immunity was Nageli's conception of the Kampf ums Dasein illustrated both by phagocytosis, and now by Buchner's alexines.56 However accurate Buchner's history may be judged in retrospect, what is important is that for him it was very real. Buchner felt, and rightly perhaps, that he was in the vanguard 52. Ibid., 833. 54. Ibid., 436.

53. Ibid., 38 (1891), 435-437, 454-456. 55. Ibid. 56. Ibid., 437.

49

ROBERT KOHLER

of a great new development in biomedical science. Also very real was his complaint that pathologists had not heeded his demonstration that the chemical substances in bacteria and not the activities of the living microbes were the true agents of disease.57

In the wave of enthusiasm over Behring's antitoxins, most pathological effects, including inflammation, were being ascribed exclusively to toxic proteins ("toxalbumins")secreted by vegetating bacteria such as tetanus or diphtheria.Buchner was well aware of the similarities of his intracellularproteins with the toxalbumins, as well as with the soluble enzymes and Behring's protein antitoxins. All belonged to one remarkable family of active, functional proteins.58But Buchner insisted that the bacterialprotoplasmproteinshad a special significance. The toxalbuminswere specific nerve toxins secreted by actively vegetating cells; the bacterial proteins were released only by degenerating cells, or cells being attacked by the body's chemical defenses: The proteins are indeed nothing other than constituents of the plasmatic cell substance. Thus we see that the young vigorouscells need to retain this substancefor further growth, while the old degenerating and dying cells in contrast spill them out into the sulroundingmedium.59 These intracellular proteins were the specific cause of inflammation and healing. Two points are worthy of note in this interesting argument. First, we again see Buchner trying to define the middle ground between the theory that infection was an act of the functioning cell and the chemical theory that infection was the effect of bacterial poisons. Buchner was feeling his way toward a workable fusion of biology and chemistry. Second, while most workers were concerned with the proteins found outside the bacterial cell, Buchner'sinterest was being focused on the proteins of the protoplasm immured within the cell wall. In the same way, most enzymologists of that time worked with enzymes secreted by cells and showed little interest in what was inside the black box. It was there that zymase was to be found, and it is not merely coincidence that it was found in Buchner's laboratory. In 1893 some experiments on toxins and antitoxins gave Buchner even more reason to be interested in the intracellular 57. Ibid., 455.

50

58. Ibid., 454-455.

59. Ibid., 455.

Eduard Buchner's Discovery of Cell-Free Fermentation proteins of bacteria.60 Despite the intense activity in the booming field of serum therapy it was still not known where toxins were produced. Some workers, such as L. Brieger (1849-1919) and Carl Fraenkel (1861-1915), believed it was animal protein made toxic by bacterial putrefaction. However, Buchner and others showed that toxalbumins were secreted by bacteria growing in broth without protein present, and Buchner concluded that the toxin came from the bacterial protoplasm: . . . the tetanus toxalbumin thus comes directly from the plasma of the tetanus bacillus, and is presumably nothing but the plasmatic substance itself, made soluble and modified in some way. The riddle of the specificity of toxic action is thus settled in a certain sense, since the protein-like substances originating from the bacterial cell will naturally retain its specific properties.0' This problem of the specificity of each toxin was a troubling one at the time, especially for those who believed that toxins originated in the infected animal. It was an even more troubling problem with regard to the antitoxins, which were universally assumed to be animal proteins of some sort. How substances so exquisitely specific for various bacterial toxins could be made from the same animal protein was hard to understand-unless they, too, like the corresponding toxins, were also bacterial in origin: VVhereas it has generally been assumed that antitoxins were products of a reactive faculty in the immunized animal organism, the capacity of which to produce the specific destruction of poison was admittedly incomprehensible, we have every reason to believe that these so-called antitoxins are purely bacterial products, constituents of the specific bacterialplasma.62 According to Buchner, tetanus toxin and tetanus antitoxin were simply different modifications of one substance, the "tetanus bacillus protein." Their specific reaction with each other was easy to understand, as was the process of immunization. Repeated injections of killed tetanus bacilli led to an accumulation of antitoxin in the blood of the animal, and this provided protection against subsequent injection of toxin alone. This theory had a most exciting practical consequence, as 60. Ibid., 40 (1893), 449-452, 480-483. Read to the Munich Society of Physicians June 7, 1893. 61. Ibid., 450. 62. Ibid., 482.

51

ROBERT KOHLER

Buchner was well aware: antitoxins might be easily obtained directlyfrom the bacteriathemselves: For bacteriotherapyall that matters is to extract and isolate the plasmatic substances of the bacterial cells in some suitable way. To first accumulate these substances in an immunized animal body and then transfer this immune serum to other organisms must, at least in theory, now be regarded as a superfluousdetour." The use of serum therapy was limited by the expensive and time-consumingproceduresfor getting immune serum and the difficulty of large-scale production. Clearly the possibility of obtaining large amounts of antitoxic protein easily, cheaply, and in relatively pure form, would revolutionize the practice of serum therapy and make the name of the man who made it work. Buchner's theory that antitoxins were bacterial proteins is another of his great expectations which he had gradually to give up, and which look worse in the history books than they did at the time. But this idea had unexpected consequences. It was about this time, in 1893, that the first experiments were done by Hans and EduardBuchneron breakingopen yeast cells by mechanical grinding, and there can be little doubt that the motive behind these experiments was Hans's hope of revolutionizing the theoryand practiceof serum therapy. Before going on to zymase, we may summarize the rather curious way in which Hans Buchner came to be interested in the intracellular proteins of bacteria. Buchner's early conversion to Nageli's theory of disease as a struggle for existence led to his theory of inflammation. Thus, while everyone else was doing the classical microbiologyALla Koch, Buchner was asking questions about the physiology of infection. His work was hardly successful, but it put him in a position to welcome and exploit the new physiological approachto immunity that began to stir about 1890. His studies on inflammationled to his idea that bacterial protoplasmicproteins were the specific cause of inflammation, and that in tumnled indirectly to the idea that toxins and antitoxins also originated in the bacterial protoplasm. The early 1890's also saw a tremendousinterest in bacterial toxalbumins,but these were treated as chemical excreta, as were the enzymes secreted by animal or plant cells. Because of his unique background,Buchner'sinterest in the proteins inside the cell was almost unique, shared by few of his 63. Ibid., 482.

52

Eduard Buchner's Discovery of Cell-Free Fermentation colleagues. It was shared, however, by his younger brother Eduard, who now appears on the scene. EDUARD BUCHNER AND THE DISCOVERYOF ZYMASE Eduard Buchner (1860-1917) was born ten years after Hans.64 After his father's death in 1872, Eduard found in Hans both father and mentor. He obviously adored and admired his successful older brother, already a regimental physician and professor, whose imposing personality was in decided contrast to Eduard's easygoing nature. Carl Harries recalled meeting Hans Buchner at Eduard's wedding in 1900: "He stood before me as a very large and stately man with a fine nose and serious but friendly eyes, brilliantly eloquent-all in all quite different from Eduard."65 The bridegroom, Harries also recalled, spent his wedding night in the police station for singing a loud comic song on a hilarious ride home through the quiet streets of Tubingen. Eduard Buchner was a forthright, good-natured, and outgoing Bavarian. He had broad interests and was an accomplished mountaineer. All these were amiable qualities that endeared him to Harries, but they were hardly the ones to win him the kind of success in the German academic world that Hans had achieved. For example: In 1904 Buchner's name was first on the list to succeed Lossen in K6nigsberg. He was telephoned by Excellency Althoff, the power of the Ministry of Culture at that time, to discuss the call. Buchner had a pressing engagement and agreed to come only if he would not be kept long. Althoff promised to keep him only 10 minutes. Buchner went, was shown to the familiar waiting room, and waited. One hour went by, and one hour and a half, and Althoff did not appear. Finally the door opened, and there sat Buchner with his watch in his hand. He pointed to the dial and demanded, "Is that 10 minutes?" whereupon Excellency Althoff angrily replied, "So you don't want to go to K6nigsberg after alll" The door slammed shut and Buchner was left sitting. This he related to me one hour after the event.66 Eduard Buchner had been intended by his father for a commercial career, but Hans more wisely enabled him to follow his own inclinations, which not surprisingly followed his broth64. C. Harries, Ber. deut. chem. Ges., 50 (1917), pp. 1843-1876. M. Gruber, Munch. Med. Wochschr. 55 (1908), 342-344. Nobel Lectures: Chemistry, 1901-1921 (Amsterdam, 1966), pp. 121-122. 65. C. Harries, Ber. deut. chem. Ges., 50 (1917), p. 1846. 66. Ibid., p. 1850.

53

ROBERT KOHILER

er's interest in science.67 In 1879 Eduard began to study chemistry at the Munich polytechinsche Hochschule, but his father's death had left the family financially straitened, and Eduard had to work for over four years in a preserve and canning factory in Munich and Momberg. In 1884 he again returned to study chemistry in Adolf Baeyer's Chemical Institute in Munich. There he workedwith TheodoreCurtius (1857-1928), and with the help of a Lamont scholarshiphe obtainedhis doctorate in 1888.68

At the same time the younger Buchner also participatedin his brother'sbiological interests and worked with him in Nageli's laboratoryin the Institute of Plant Physiology. The subject of Eduard'sresearch was alcoholic fermentation, and the result was a long paper publishedin 1886 on the role of oxygen in fermentation.69Nageli had been involved in the disputes over fermentation and upheld a version of Liebig's chemical theory in his book, Theorie der Gahrung,which appearedin 1879. In the heated debate over the role of oxygen, Nageli also opposed Pasteur'sclaim that yeast fermented less actively with air present than without. Eduard Buchner, too, criticized Pasteur's experimental procedures, but his own carefully controlled experiments confinned Pasteur's claim: fermentation per cell was greaterin the absenceof air. In 1890 Eduard was made assistant in Baeyer's teaching laboratory,and in 1891 he habilitated as privatdozent.Apparently he also kept up his other interests too, for Richard Willstatter,then a bright and very ambitiousyoung graduatestudent, later recalled: "EduardBuchner was the assistant for the organic laboratoryat the time; the students were forced to rely on themselves."70 But Baeyer himself had some interest in fermentation, since he had published a speculative paper in 1870 on a chemical mechanism for the transformationof glucose to alcohol and carbon dioxide.71 Through Baeyer, Eduard received a special grant to set up a small laboratoryfor the study of fermentation and to give lectures and demonstrations on fermentation.72In this laboratorythe first experiments on grindingyeast were done, though not with the aim of finding out about fermentation. It was unusual at the time for structural organic chemists to be interested in biological problems 67. Nobel Lectures (n. 64 above), p. 122. 68. 69. 70. 71. 72.

54

Ibid., 122. E. Buchner, Z. physiol. Chem., 9 (1886), 380-415. R. Willstitter, From My Life (New York, 1966), p. 47. A. Baeyer, Ber. deut. chem. Ges., 3 (1870), 63-75. Nobel Lectures (n. 64 above).

Eduard Buchner's Discovery of Cell-Free Fermentation (Emil Fischer being the most notable exception), and it was a rare concurrence of events, namely, Baeyer's old interest in fermentation and Eduard's famliy connection with Nageli's group, that allowed Eduard to conduct experiments on yeast in 1893. Hans Buchner's interest in bacterial protoplasmic protein was running high. The usual way of isolating protein from cells was Nencki's chemical extraction, a rough process that would surely damage the delicate proteins and decrease their specific activity. In fact, Buchner's preparations were much less active than whole cells, and undoubtedly Buchner hoped to increase their activity by gentler extraction. Other chemical methods were no better-week-long trituration with water or treatment with hot aqueous glycerine (Koch's method for preparing tuberculin).73 Naturally Hans consulted his chemist brother, and in their discussions they reached the conclusion that cells must be opened by purely mechanical means. Though it had been stated that bacteria could not be broken open by grinding, it was well known to practical microscopists that careless rubbing of yeast between microscope slides often led to rupture of the cells.74 Eduard's first attempts to open yeast cells by familiar methods failed, but rubbing with sand, he found, did the trick nicely: My first attempts to burst the cell membrane of yeast by freezing to -160 and rapid thawing did not succeed. The membrane is much too elastic for it to be broken in this way. Direct grinding in a mortar had as little success, because the pestle could not get a purchase on such elastic stuff. In contrast, it turned out (1893) that even the smallest microorganism, e.g., the smallest forms of Friedlander's pneumococcus [N.B.] could be ground up by the addition of fine sand. The process could be directly controlled microscopically. As it later transpired, Liidersdorff had ground wet yeast as early as 1846. I thank Adolf von Baeyer for first bringing this fact to my attention.75 Buchner used yeast for the trial experiments: in a brewing town yeast was cheap and readily available. But clearly once the method succeeded he tried bacteria as well: after all, the real object of these experiments was the proteins of pathogens such as pneumococcus. The hard part of the problem being neatly solved, the easy 73. E. Buchner, H. Buchner, and M. Hahn, Die Zymase (Munich, 1903), p. 15. 74. Ibid., p. 16. 75. Ibid.

55

ROBERT KOHLER

part provedunexpectedlydifficult-namely, isolating the soluble protoplasmicproteins from the sand and cell debris. The only obvious way was by repeated dilution with water and simple filtration, but this method leads to loss of material and loss of activity due to dilution.76Apparentlyexperiments on immunization were carried out with proteins obtained in this way, but if so, there were no results worth publishing. Despite the success of sand-grinding,the results on the whole must have been discouraging. But the sand-grinding technique was promising and potentially valuable, and in 1893 Eduard applied for a patent.77The patent was refused, probablywhen it appeared that the same method had not only been tried long before by Ludersdorff, Mannesein, and Mayer,78but that it was enjoying quite a vogue in the early 1890's among mycologists, who used it to increase the yield of invertase from yeast and fungi. It was applied in 1890 by M. A. Fembach (1860-1939) at the Pasteur Institute:79 in 1892 by Carl Amthor (1853-? ) at the Chemical Research Station in Elsass, in a study related to beer manufacture;80 and in 1893 by E. Bourquelot(1851-1921), the noted mycologist and enzymologist.81In 1894, after Buchner's work, Max Cremer at the PhysiologicalInstitute at Munich used sand-grinding to get glycogen out of yeast,82 and in the same year Emil Fischer used the same method to get sugar-splittingenzymes from various microorganisms.83No wonder, then, that Eduard's application for a patent began to look somewhat presumptuous. An interesting feature of this spate of sand-grindingis that except for Cremer,who mentioned Marie Mannesein and could well have known of Buchner's work next door, all the others failed to give a reference for the method. Moreover,they described it in a matter-of-factway, as if it were common knowledge. Fernbach's variant did resemble Liidersdorff's,as Bourquelot'sdid Mayer's,but otherwise there are no clues as to how 76. M. Hahn, Munch. Med. Wochschr., 55 (1908), 515-516. 77. H. Buchner, Munch. Med. Wochschr., 34 (1897), 322. (Heidelberg, 78. A. Mayer, Lehre von den Chemischen Fernenten 1882), p. 14. 79. M. A. Fernbach, Ann. l'Inst. Pasteur, 4 (January 1890), 1-24, esp. 19-24. 80. C. Amthor, Z. Angew. Chem., 6 (1892), 318-320. Abstracted from Z. Ces. Brauw., 1892. 81. E. Bourquellot, Bull. Soc. Microbiol. France, 9. (1893), 189-194. 82. M. Cremer, Z. Biol., 31 (1894), 183-190. 83. E. Fischer, Ber. deut. chem. Ges., 27 (1894), 3479-3483, and 28 (1895), 3034-3039.

56

Eduard Buchner's Discovery of Cell-Free Fermentation this practical knowledge became current. Why the curious nonchalance about giving a source for a method that was hardly a textbook method? Buchner probably did not get the idea of sand grinding from any published source, certainly not Ludersdorff or Mannesein. However, the method was probably known in a vaguer, more underground way by some groups, such as the mycologists, as a useful aid to extraction, without the original sources being known. Sand grinding may also have been a fairly commonly used method among physiologists for extracting organ tissue. W. Kuhne, for example, mentions grinding pancreas with powdered glass and absolute alcohol,84 and I suspect many similar reports could be found. Buchner, working among physiologists, could very well have been drawing on this practical tradition, unaware that it had been applied to yeasts. In any case, when it became clear that Buchner's new method was not as novel as he had thought, the Board of the Chemical Laboratory, reviewing his grant, intervened and told him to spend his money in a more profitable way: . . . because the Board of the Laboratory was of the opinion that "nothing will be achieved by this"-the grinding of yeast cells had already been described during the past 40 years, which latter statement was confirmed by accurate study of the literature-the studies on the contents of yeast cells were set aside.85 Buchner was in a rather difficult situation. The experiments on yeast per se were not novel, being after all only the preliminary to work on bacteria. But since Hans's work was not within the scope of his grant or the interest of any chemist, Eduard could hardly justify his work in this way. Moreover, it appears that his divided attention to chemistry and Hans's medical interests did not help his reputation among his fellow chemists. At that very time, in fact, Eduard was passed over for promotion in favor of H. Rupe, a younger man than himself. Willstatter later wrote: Buchner never got over this slight and bitterly resented Baeyer personally, as well as his circle, because of it. The great success of his work on cell-free fennentation . . . granted Buchner a brilliant rehabilitation. When the first 84. W. Kiihne, "Bemerkungen t5ber Enzyme und Fermente," Unters. aus d. Physiol. Inst. Univ. Heidelberg, 1 (1877), 318. 85. Nobel Lectures. The source of this detail is not given, but the brief biography was probably written by Buchner himself.

57

ROBERT KOHLER

communication appeared . . . Baeyer said to me, "this will

make him famous even if he has no talent for chemistry."86 In the fall of 1893 Eduard went to join his former teacher Curtiusin Kiel and there he became professorin 1895. In 1896 he moved to Tiubingen,where he stayed until 1898, when he went to the agricultural college in Berlin, closer to the center of fermentation research.87The experiments on grinding bacteria were given up when Eduard left Munich, and Eduard himself did not pursue them. It is safe to assume that the results in hand did not encourage putting more time and money

into the project. Hans pursued his studies of alexines, and Eduard continued the more pedestrian chemical researchesbegun with Curtius. In 1894 an event took place that removed any institutional impediments to work on bacterial proteins: Hans Buchner was chosen to succeed the renowned Pettenkoffer to the chair of hygiene and directorship of the Institute. His appointment, which caused some surprise and controversy,was oddly enough due to his association with Nageli.88Naigelihimsef was neither a medical man nor a hygienist, but he had been one of the early supporters of the germ theory of disease. His protege, Buchner, was an M.D. and a microbiologist, and his work in immunity was widely known. The other candidates were prot6g6s of the other great men of Munich science-Pettenkoffer and the physiologist Carl Voit. But Pettenkofferwas still a determined opponent of the germ theory of disease, and Voit's ideas on metabolism were becoming increasingly out of date. So Nageli proved to be the most far-sighted of the Munich favorite sons, and Buchner was awarded the chair. The important place in history that Buchnerhad given Niigeli in his 1891 lecturemust have seemed finallyto be vindicated. Though Hans now had funds and facilities at his command, he was deeply involved with defending his alexines, and it was not until the summer of 1896 that he returned to the problems of preparing bacterial protein. Buchner set his assistant, Dr. Martin Hahn (1865-1934),89 the problemof making the sandgrinding method workable. The separation of the cell juices 86. R. WilLstatter,From My Life, p. 66. Willstatter's attitude may not be untouched by malice. He was the leader of a school of thought bitterly opposed to Buchner's conception of intracellular enzymes. In his last paper in 1940 Willstatter was still arguing that zymase was simply an altered piece of colloidal protoplasm, Ibid., 441. 87. C. Harries, Ber. deut. chem. Ges., SO(1917), pp. 1850-1853. 88. F. Hueppe, M{unch.Med. Wochschr., 49 (1902), 844. 89. Anon., Ber. deut. chem. Ges., 69A (1934), 173.

58

EduardBuchner'sDiscoveryof Cell-FreeFermentation from sand and cell debris Hahn achieved in a most ingenious way. He added kieselguhr to the sticky mass of ground yeast until it became a friable mass. He then wrapped this in cloth and pressed it in a hydraulic press. The cell debris was filtered out by the kieselguhr, and an opalescent yellowish juice was expressed, up to 400 cc from 1 kg of yeast. This was undiluted intracellular juice, almost free of whole cells and rich in dissolved protoplasmic proteins.90With this juice Hahn carried out experiments on animals (of what sort he did not say). In doing these experiments, however, Hahn noticed that the extracts spontaneously decomposed, rapidly losing their coagulable protein. Antiseptics added to the extracts used for injections did not prevent breakdown,and even caused precipitation. At the end of the summer Hahn reported to Hans Buchner his successful method of getting press juice, and also the mysterious instability of the extracts. They agreed that other common preservativesshould be tried, such as concentrated salts, glycerine, or 40 percent glucose. Hahn then left for his vacation. A few days later Eduard Buchner arrived to spend his vacation in Munich working on press juice. He had naturally been kept informed by Hans about the progress of the work. Experiments with preservativeswere already under way when Eduardcame into the laboratory,and he noticed that an extract in 40 percent glucose was generating a steady stream of bubbles. Having worked with fermentation himself, Eduard recognized what he saw as a fermentation. That it was a cell-free fermentation apparently became clear only gradually and through many more experiments. Hans Buchner later admitted he had believed at first that the fermentation was due to large fragments of living protoplasm that slipped through the ifiter, and not to true soluble ferments.91 However, fermentation also appeared in extracts treated with a variety of antiseptics which theoretically should stop the action of living protoplasm as they did that of living cells. Within a month or two, Hans and Eduardwere convinced, and Hans wrote to Hahn that true cell-free fermentation has been discovered.92After Eduard's return to Tubingen, further experiments were carried out by 90. M. Hahn, Munch. Med. Wochschr. 55 (1908), 515-516. Hahn wrote his account of the discovery of zymase to belay the suggestion of M. Gruber (ibid., 342-343) that he had missed zymase because he had not had his eyes open.

91. H. Buchner, Munch. Med. Wochschr., 44 (1897), 299-302, 321-322. Discussion at a meetting of the Society for Morphology and Physiology, March 16, 1897. 92. M. Hahn, Munch. Med. Wochschr., 55 (1908).

59

ROBERT KOHLER

Hans's assistant, R. Rapp. On January 9, 1897, the first paper on zymase was received for publication, and in the spring it appeared to an astonished and largely incredulous world.93 While Eduardpursuedthe study of zymase, Hans Buchnerand Martin Hahn continued the work for which the grinding of yeast had been a mere preliminary.With some difficulty,they managed to get extracts of protoplasmicprotein, or "plasmine," as Buchner named it, from various pathogenic bacteria.94But if they had hoped that plasmines obtained mechanically would have greater biological activity than those extracted chemically they must have been disappointed. For example, cholera-plasmine was toxic, but only in large doses, and the inflammation it caused was much less markedthan that caused by an equivalent amount of killed cholera bacilli. Cholera plasMie also conferred immunity on animals, but no more effectively than heat killed cells. Similar results were obtained with typhus, but with anthrax and staphylococci the results were negative. In short, Buchner'stheory of intracellularproteins was supported, but not in a very striking way, and the hopes for practical ap-

plicationwere dashed. By a curious coincidence Buchner again collided with Koch, who announced early in 1897 that he had obtained a new tuberculin by grinding tubercle bacilli with sand.95 He hoped that mechanical extraction would leave material more intact and therefore more specific and less easily resorbed. Hans Buchner quickly replied,96again laying claim to the theory behind Koch'swork and to priorityfor his method as well. Had the 1893 patent been approved,he ruefully noted, his claim to the method of sand-grinding would have been clear. Koch's right to the scientific credit Buchner did not dispute; his own work on tubercle plasmine has become bogged down in technical problems.97 As it turned out, the theory that played so important a role in Hans Buchner'scareer and that made the protoplasmicproteins seem so important for immunity was a red herring. The specific antigens of bactenraturned out to be polysaccharides of the cell envelope, whereas the intracellular proteins and enzymes were much the same for all cells. That idea, in fact, 93. E. Buchner, Ber. deut. chem. Ges., 30 (1897), 117-124. 94. H. Buchner, MiZnch. Med. Wochschr., 44 (1897), 1342-1343. M. Hahn, ibid., 1344-1347. Read to the Munich Society of Physicians November 10, 1897. 95. R. Koch, Deut. Med. Wochscht., 23 (1897), 209-213. 96. H. Buchner, Berliner klin. Wochschr., 34 (1897), 322-323. 97. M. Hahn, Munch. Med. Wochschr., 44 (1897), 1346ff.

60

Eduard Buchner's Discovery of Cell-Free Fermentation became one of the basic tenets of the new science of biochemistry-the unity of cell metabolism. But in a far more important way Hans Buchner's theory was a most important positive contribution to the emerging science of biochemistry. It called attention to the importance of studying intracellular proteins, the active agents of cell metabolism. It led to the discovery of how the black box of the cell could be opened up. The BuchnerHahn method of getting press juice revolutionized the study of intracellular enzymes, and led to a rapid increase in the number of known intracellular enzymes. Finally, Buchner's theory, descended in so curious a way from Nageli's, was responsible for the discovery of zymase, the most important precedent for the belief that all vital functions of the cells were due to the activity of enzymes. This new belief was soon to become the keystone of the new science of biochemistry.98 Acknowledgements This paper was prepared while the author was a Macy Postdoctoral Fellow in the Department of the History of Science at Harvard University. It is a pleasure to thank the Macy Foundation for their generous and welcome support. A preliminary account was presented to the East Coast Conference on the History of Biology, May 1969. 98. A study of the tumultuous reception of Buchner's discovery and the controversy between the enzyme and protoplasm view is forthcoming.

61

Organismicand HolisticConceptsin the Thoughtof L. J. Henderson JOHN PARASCANDOLA School of Pharmacy and Department of the History of Science University of Wisconsin Madison, Wisconsin

In the increasingly complex and specialized world of the twentieth century, the scholar who makes professional contributions to several differentfields has become more and more of a rarity. The crossing of the lines which separate the traditional subjects of the academic curriculum requires a very special kind of man. Lawrence Joseph Henderson, who taught at Harvard from 1905 until his death in 1942, was such a man. At various times throughout his career, he took a professional interest in physical chemistry, biochemistry, physiology, medicine, philosophy, sociology,and the historyof science. In spite of this diversity of interests, his work exhibits in retrospect a fundamental unity. He himself felt in his later years "that there had been more interconnections between the things that I had done, even more unity in some sense in my thinking and my work than I was aware of or can now recover in my memory."1There is a marked similarity in his approach to problems in these various fields. His early work seems to have impressed him with the need for studying the interaction between the variables of a system, and with the apparentorderliness of certain systems. His career was largely devoted to the study of the organizationof the organism, the universe, and society. The emphasis in his work was always on the need to examine whole systems and to avoid the error of assuming that the whole was merely the sum of its parts. Of course, this apparent unity in his approach was not the result of some preconceivedplan. He merely followed his own interests, and one study led to the next. It was during the course of his experimentalresearches that his methodologyand philo1. L. J. Henderson, "Memories," MS, 1936-1939, Widener Library Archives, Harvard University, p. 194. See also ibid., p. 1. Journal of the History of Biology, voL 4, no. 1 (Spring 1971), pp. 63-113.

63

JOHN PARASCANDOLA

sophic outlook evolved and became explicit. In his "Memories," an unpublished autobiographical manuscript written in the period 1936 to 1939, he noted that while writing The Fitness of the Environment (1913), he had occasion to refer to nearly every piece of scientific work that he had previously done because these were pertinent to the problem at hand. Yet he said that he felt sure that very few of these papers were determined by an awareness of the question of fitness. Rather, his researches on acid-base equilibria had led him to consider this question.2

The career of L. J. Henderson involved a progressionfrom the study of simple and artificial systems, such as aqueous solutions of phosphates, to the investigation of complex and natural systems, such as blood and society. During the course of this progression, his philosophical views underwent considerable change, although ideas such as system, equilibrium, organization, and fitness retained their place in his thinking throughouthis mature life. This paper will deal with the origin and development of these concepts in Henderson's thought, especiallyin relationto his biologicalresearches.3 Henderson's holistic, organismic approach reflects an important trend in the science and philosophy of his time.4 The development of field theory and relativity theory in the early twentieth century led to less emphasis in physics on mechanical models and on substance. Matter came to be viewed essentially as an activity or process."The concepts of modem physics led 2. Ibid., p. 194. 3. I have discussed the role played by such concepts in Henderson's sociological views and in his philosophy of nature in more detail elsewhere. See John Parascandola, "Lawrence J. Henderson and the Concept of Organized Systems," unpub. dis., University of Wisconsin, Madison, 1968.

4. For discussions of organismic and holistic views in twentieth-century science and philosophy, see W. E. Ritter and E. W. Bailey, "The Organismal Conception, Its Place in Science and Its Bearing on Philosophy," Univ. Calif. (Berkeley) Publ. Zool., 31 (1928), 307-358; William M. Wheeler, Emergent Evolution and the Development of Societies (New York: W. W. Norton, 1928); R. L. Schank, The PermnanentRevolution in Science (New York: Philosophical Library, 1954); Ludwig von Bertalanffy, Modern Theories of Development: An Introduction to Theoretical Biology, adapted and trans. by J. H. Woodger (London: Oxford University Press, 1933) pp. 46-66; Ludwig von Bertalanffy, Problems of Life: An Evaluation of Modern Biological Thought (New York: John Wiley, 1952), pp. 176-204; R. G. Collingwood, The Idea of Nature (London: Oxford University Press, 1945), pp. 9-27, 133-177. There was no one school of organicism or holism, but rather a number of very different theories which shared a common emphasis on the unity and organization of the whole. 5. See, for example, R. J. Blin-Stoyle, 'The End of Mechanistic Phi-

64

Organismicand Holistic Conceptsof L. J. Henderson Alfred North Whitehead, who became a close friend of Henderson'swhen he moved to Harvard,to formulate his theory of "organicmechanism." Whitehead defined science as the study of "organisms,"and this term included any organized system, whether it was a living being or an atom.6 Other twentiethcentury philosophical movements, such as "emergent evolution," expounded by Lloyd Morgan and others, and General Smuts's holism, were also based on the idea that the characteristics of a whole are due to the nonadditive interactions between the parts.7 Organismic and holistic views also invaded the area of social science, as illustrated, for example, by the functionalist school in anthropologyand the gestalt theory of psychology.8

A school of "organismic"or "organismal"biology has also developed in the twentieth century, and is associated with the names of Ludwig von Bertalanffy,J. H. Woodger,William Ritter, and others.9 This approach, says Bertalanify, takes from mechanism the knowledge that the characteristicproperties of life are based on material systems, and from vitalism the recognition of the wholeness of vital phenomena.10The organismic theory "sees the essence of the organism in the harmony and coordination of the processes among one another, but, on the losophy and the Rise of Field Physics," in Turning Points in Physics (Amsterdam: North-Holland, 1959), pp. 5-29; Albert Einstein and Leopold Infeld, The Evolution of Physics: The Growth of Ideas from Early Concepts to Relativity and Quanta (New York: Simon and Schuster, 1938), pp. 71-260; Max Jammer, Concepts of Mass in Classical and Modern Physics (Cambridge, Mass.: Harvard University Press, 1961), pp. 85-224. 6. See Alfred North Whitehead, Science and the Modern World (Cambridge, England: Cambridge University Press, 1926). 7. C. Lloyd Morgan, Emergent Evolution (London: Williams and Norgate, 1923); J. C. Smuts, Holism and Evolution (New York: Macmillan, 1926). 8. On organismic and holistic theories in the social sciences, see Loren Eiseley, Darwin's Century: Evolution and the Men who Discovered It (Garden City, N.Y.: Doubleday, 1958), pp. 340-349; Bertalanffy, Problems of Life, pp. 189-194; 0. L. Reiser, "Gestalt Psychology and the Organismic Theory", J. Soc. Phil., 4 (1939), 260-271; N. S. Timasheff, Sociological Theory, Its Nature and Growth (Garden City, N.Y.: Doubleday, 1955), pp. 219-229. 9. On organismic biology, see Bertalanffy, Theories of Development; Bertalanffy, Problems of Life; Ritter and Bailey, "The Organismal Conception," pp. 307-333; Giovanni Blandino, Theories on the Nature of Life (New York: Philosophical Library, 1969), pp. 155-209. For a criticism of this philosophy, see Morton Beckner, The Biological Way of Thought (New York: Columbia University Press, 1959). 10. Bertalanffy, Modern Theories of Development, p. 188.

65

JOHN PARASCANDOLA

other hand, does not interpret this coordination as vitalism does, by means of a mysterious entelechy, but through the forces imanent in the living system itself."11Biologicalorganization was considered to be a scientific problem, subject to experimental investigation. Knowledgeof the mechanisms which regulate and coordinate vital phenomena is essential for understandingthe phenomena of organization, and a great deal of research was focused on the problem of regulation in the first half of the twentieth century. In this connection, Claude Bemard's theory of the constancy of the milieu int6rieur, which received only limited attention in the nineteenth century, became an important general concept in physiological thought. J. S. Haldane, Walter Cannon, Joseph Barcroft,Charles Sherrington,L. J. Henderson, and others worked to elucidate the body's regulatory mechanisms and to discover how these are coordinated to maintain stable conditionsin the internal environment.12 FrederickL. Holmes has argued that Bemard'sconcept of the milieu int6rieur served these physiologists as an aid to interpret-

ing researches already begun independently of it, rather than as a stimulus to undertake experimentalresearches on regulation.'s Joseph Barcroft, Holmes has shown, did not mention the idea of the internal environment or appear to be visibly influenced by it in any of his work from 1900 to 1929.14 Garland Allen has demonstrated that Haldane's work on the regulation of breathing also supports Holmes's view. Haldane became involved with the problemof respiratorycontrol through his work for the governmentinvolving the study of vitiated air in sewers, factories, public buildings, and so forth. It was only after the physiological problem was more or less solved that Haldane came to think of respiratoryregulation in terms of Bernard'stheory of the constancy of the internal environment. In his early work on this subject, he did not mention the milieu 11. Ibid.,pp. 177-178. 12. For discussions of the importance of the theory of the internal environment in the work of these men, see Reino Virtanen, Claude Bernard and His Place in the History of Ideas (Lincoln: University of Nebraska Press, 1960), pp. 80-97; E. H. Olmsted, "Historical Phases in the Influence of Bernard's Scientific Generalizations In England and America," in F. G. Grande and M. B. Visscher, ed., Claude Bernard and Experimental Medicine (Cambridge, Mass.: Schenkman, 1967), pp. 24-34; F. L. Holmes, "Claude Bernard's Concept of the Milieu Intrieur,,"

unpubL diss., Harvard

University, Cambridge, Mass., 1962, pp. 246-264. 13. Holmes, "ClaudeBernard'sConcept,"pp. 256-259. 14. F. L. Holmes, "Joseph Barcroft and the Fixity of the Internal Environment,"J. Hist. Biol., 2 (1969), 89-122.

66

Organismicand Holistic Conceptsof L. J. Henderson int6rieur

or organic regulation.'5 Russell Maulitz has demon-

strated that the same is true for Walter Cannon, who was apparently concerned in his initial researches with the problems of shock treatment and adrenal secretion. Maulitz indicates that later Cannon came to the concept of the. constancy of the internal environment as a summarizing generalization.'6Henderson's case also offers evidence for Holmes's contention. Bemard's theory did not serve as the stimulus for his research

on neutrality regulation, and this work was largely completed before he mentioned the milieu int&rieur. Even then, as we shall

see, he made little use of this concept until several years later, when he was alreadyinvolvedin his researcheson blood. According to Henderson, he already possessed by his sophomore year at Harvard"a vague feeling that there are not only many undiscoveredsimple uniformities behind the complexities of things but also undiscovered unifying principles and explanations." At that time, he was introduced to the periodic classification of the elements, and he felt that there must be some explanation, such as that expressed by Prout'shypothesis, for the orderwhich the elements exhibited.17 During his undergraduateyears at Harvard (1894-1898), he was especially attracted to physical chemistry, which was taught by T. W. Richards.His training in this area undoubtedly impressed him with the importance of the concepts of equilibrium and system, which played an important part in all of his future work. At this time, physical chemistry had already begun to demonstrate its value for biology, and Henderson became interested in the application of physicochemicalmethods and principles to biochemical problems. In order to receive training in the biological sciences, he decided to attend Harvard Medical School, where he obtained his M.D. in 1902. The next two years were spent in the Strassburglaboratoryof Franz Hofmeister, one of the pioneers in the application of physical chemistryto biochemistry. In the fall of 1904 he returned to Harvard to work with T. W. Richards on thermochemicalstudies. While an undergraduate, he had already concluded that Julius Thomsen's method of estimating the heat of combustion of an organic compound by summing up the heats of combustionof each of the valences 15. G. E. Allen, "J. S. Haldane: The Development of the Idea of Control Mechanisms in Respiration," J. Hist. Med., 22 (1967), 392-412. 16. Russell Maulitz, "Walter B. Cannon: Scientfic Explanation in Regulatory Physiology," unpubl. diss., Harvard University, Cambridge, Mass., 1966. 17. Henderson, "Memories,"p. 16.

67

JO}IN PARASCANDOLA

did not always work.'8In a paper publishedin 1905, Henderson brought together an impressive amount of data from the literature to show that the heat of combustion of a particular valence varies with its position in the molecule.'9 The heat of combustion of an atom chemically bound in a molecule is dependentnot only upon its nature and the nature of the atoms with which it is directly united, but also upon the nature and position of every other atom of the molecule.20 The chemical molecule in this sense is an excellent example of a integrated system with a number of variables in a state of mutual dependence. Yet at the time, as Hendersonlater admitted, he did not clearly realize and consider "the importance and wide bearing of this idea in its most general form."2' It was to take years of research upon other organized systems before he generalized this concept and made it the basis of his methodology. These early experiences seem to indicate, however, that he possessed the type of mind which, as CraneBrinton phrased it, "was always seeking the broadest generalizations that the data could bear."22 At this point in his life, his philosophicaloutlook was that of a "naiverealist."As he later noted: I am just old enough to have experienced the old comfortable assurance that the world of science is stable, true and real; that not only the facts and uniformities but also the theories and conceptual schemes are on the whole such that they will endure with nothing more than improvements, refinements, and occasional corrections, and that they

will be marredonly by an occasionalminor catastrophe.23 After a semester of work in Richards'laboratory,Henderson was appointed to teach biological chemistry at Harvard. He decided to abandon his thermochemicalstudies in order to become involved in biochemical research.24As an undergraduate, 18. Ibid., pp. 36, 81. 19. L. J. Henderson, "The Heats of Combustion of Atoms and Molecules," J. Phys. Chem., 9 (1905), 40-56. Henderson stated in his "Memories,"pp. 78-81, that he compiled this data in 1902 and 1903 while at Strassburg. An earlier version of this paper, he noted ("Memories,"pp. 81-82), was rejected for publication in Zeitschrift fur Physihalische Chemie. 20. L. J. Henderson, "The Heats of Combustion,"p. 55. 21. Henderson, "Memories,"p. 82. 22. Crane Brinton, "Lawrence Joseph Henderson, 1878-1942," in E. W. Forbes and J. H. Finley, Jr., ed., The Saturday Club: A Century Completed: 1920-1956 (Boston: Houghton Miffin, 1958), p. 209. 23. Henderson, "Memories," pp. 119-120.

24. Ibid., pp. 121-122.

68

Organismicand Holistic Conceptsof L. J. Henderson he had come across a paper by Richard Maly, the physiological chemist, dealing with the diffusion of acidic and aklaline phosphate salts.25 This paper, which was published in 1876 but apparentlyattractedlittle attention, had set Hendersonthinking about the acid-base balance of the body.26Thus, in 1905, he decided to focus his first experimental investigations in biochemistryon this problem. His studies on the equilibriumin aqueous solutions of phosphates led him to derivehis famous equation, (H+)

k(acid) (salt)

which quantitatively described the action of buffer solutions, i.e. solutions which resist changes in acidity or basicity.27The equation also made it clear that a weak acid and its salt will act most effectively as a buffer at a hydrogen ion concentration, (H+), equal to the acid'sdissociationconstant, k. This explained why carbonic acid and monosodium phosphate, along with their salts, acted so efficiently in preserving the approximate neutrality of the body. These acids have dissociation constants of about 10- mole per liter, which means that they serve as excellent buffers for blood and many other physiological fluids, in which the hydrogenion concentrationis close to 107 mole per liter, the point of neutrality. It was obvious that blood and protoplasm are complex, heterogeneoussystems, not directly comparableto simple buffer solutions of phosphates. Henderson thus turned his attention to artificial buffer systems which contained several of the constituents of protoplasm.He investigated the propertiesof a twophase, multicomponent system, consisting of gaseous carbon dioxide in contact with an aqueous solution of bicarbonate and mono- and dihydrogenphosphate.28On the basis of these studies, he offered,in 1908, a theoreticaldiscussion of the heterogeneous 25. Richard Maly," Ueber die Aenderung der Reaction (in der Lisung eines Salzgemisches) durch Diffusion und die dadurch mogliche Erklarung beim Vorgange der Secretion von saurem Harn aus alkalischem Blute,' Ber., 9 (1876), 164-172. 26. Henderson, "Memories,"pp. 36-37, 122-123. 27. L. J. Henderson, "Concerningthe Relationship between the Strength of Acids and Their Capacity to Preserve Neutrality," Am. J. Physiol., 21 (1908), 173-179. 28. L. J. Henderson and 0. F. Black, "A Study of the Equilibrium between Carbonic Acid, Sodium Bicarbonate, Mono-sodium Phosphate, and Di-sodium Phosphate at Body Temperature," Am. J. Physiol., 21 (1908), 420-426.

69

JOHN

PARASCANDOLA

buffer systems of the body.29He concluded that the bicarbonates constitute the body's first reserve in neutralizing acids, with the phosphates acting as second reserve. To other buffers, such as the proteins, he assigned a secondaryrole. At this time, he considerably underestimated the importance of protein buffers. These physiological buffer systems, Henderson pointed out, are much more efficient than a simple solution of a weak acid and its salt. For example, it is difficult to produce a significant change in the ratio of H2C00/NaHCO8in the body, because the rate of respirationcan be varied in orderto increase or decrease the amount of carbonic acid in the blood. In addition, it is obviousthat the neutralizationof acids by NaHCO3and Na2HPO4 is only the first step in protecting the body against acidosis. The weak acids formed by this neutralization, H2co3 and NaH2PO4,must eventually be removed from the body in order to return it to its normal buffer capacity. He noted that carbonic acid is easily and quicklyremovedfrom the field of action by excretion in the lungs; a nonvolatile acid could not be removed as efficiently. The fact that NaH2PO4diffuses more rapidly than Na2HP04 provides a possible mechanism for acid phosphate to escape from the body into the urine, and this increases the efficiency of the phosphate buffer system. The body, he added, is also safeguarded against an increase in alkalinity. Carbonic acid is constantly being produced and must quickly convert any excess of strong base into the weakly basic bicarbonate ion. As the concentration of sodium bicarbonate increases in the blood, it produces a rise is osmotic pressure which the kidneys act to offset by excreting more bicarbonate. Henderson's general conclusion was that the physiological mechanisms involved in the maintenance of neutrality possessed "a remarkableand unsuspected degree of efficiency"and "a high factor of safety."30These facts made a profound impression on his mind and laid the groundworkfor his philosophical speculationsof the next decade. It became clear to him, on the one hand, that the efficiency of neutrality regulation depended in part upon the peculiar properties of certain substances (the dissociation constants of carbonic acid and monosodium phosphate, the gaseous nature of carbon dioxide which 29. L. J. Henderson, "The Theory of Neutrality Regulation in the Animal Organism'" Am. J. Phy8tol., 21 (1908), 427-448. The following discussion of Henderson's views on the buffer systems of the body is based on this paper. 30. Ibid., pp. 447-448.

70

Organismic and Holistic Concepts of L. J. Henderson

allows it to be readily excreted, etc.). His interest in the "fitness" of these substances in physiological processes was thus aroused.3'On the other hand, it was obvious that the acid-base balance is intimately related to other bodily processes, and that such interrelations aid in the maintenance of neutrality. For example, as already noted, the rate of respirationcan be varied in order to increase or decrease the amount of carbon dioxide in the blood. In addition, the kidneys, through the excretion of acidic or basic substances, play a vital role in the organism's acid-base equflibrium. Such considerations were probably instrumental in directing Henderson's attention to the questions of self-regulationand biologicalorganization. At about this same time (1908), he began to attend Josiah Royce's seminar in logic, apparently at the suggestion of his friend Ernest Southard, the psychiatrist. His continued attendance at this seminar over a number of years stimulated his interest in philosophical questions, as well as acquainting him with the works of A. N. Whitehead, Bertrand Russell, and others.32Although he could not accept most of Royce's views, Hendersonacknowledgeda debt to the philosopherin the preface to his The Fitness of the Environment (1913):

"His learning

and generosity have in the past aided me to reach an understanding of the philosophical problems of science, and in the preparation of this book they have repeatedly guided me aright."33

It is possible, in fact, that Royce's own belief in a kind of universal teleology may have contributedto Henderson'sinterest in the question of "fitness."34 In any case, Royce was

enthusiastic about this work and attemptedto call the attention of his fellow philosophers to the book.35Shortly after its publication, Henderson and Royce established an informal club of certain Harvardfaculty members for the discussion of problems in the history and philosophy of science. This club, which existed for about a decade, enabled Henderson to exchange ideas on scientific method and philosophy of science with his colleagues on a regularbasis.86 31. Henderson, "Memories,"p. 134. 32. Ibid., pp. 151-154. 33. L. J. Henderson, The Fitness of the Environment: An Inquiry into the Biological Significance of the Properties of Matter (New York: Macmillan, 1913), p. di. 34. See, for example, Josiah Royce, The World and the Individual (New York: Macmillan, 1901), II, 42, 224-233. 35. Letter from Josiah Royce to L. J. Henderson, March 22, 1913, Widener LibraryArchives, Harvard University. 36. Henderson, "Memories,"pp. 209-212.

71

JOHN PARASCANDOLA

Henderson'sunderstandingof the general problemsof science was also increased by the preparationinvolved in his history of science course, which he began teaching in 1911. His interest in this subject had apparentlyfirst been aroused while still an undergraduatewhen he heard T. W. Richards'lectures on history of chemistry.87All of these activities resulted in a good deal of reading and thinking about philosophical issues, and probably encouraged Henderson to speculate on the implications of some of his researches. It was in the decade or so following 1911 that he developed his views on the organizationof the body and the order of the universe. A paper published in that year, entitled "A Critical Study of the Process of Acid Excretion," shows that he had already begun to think about these subjects. This article began as follows: The right working of physiological processes depends upon accurate adjustment and preservation of physicochemical conditions within the organism. Three such conditions, temperature, molecular concentration, and neutrality are now known to be nicely adjusted and maintained; adjusted by processes going on inside the body, maintained by exchanges with the environment.88 The above statement indicates that Hendersonhad begun to consider other regulatory processes besides neutrality regulation, and to realize that the latter was only one aspect of the problem of self regulation in general. The fact that he stressed the importance of maintaining constant physicochemical conditions within the organism without even mentioning the internal environment suggests that he had not yet associated the regulatory mechanisms with this doctrine. The concept of physiologicalregulation,however, existed long before the theory of the milieu intrieur.39 Holmes has pointed out that, even in the second half of the nineteenth century, iMvestigationson the maIntenance of the propertiesof blood were generally pursued independently of Bernard's theory.40Although one would suspect that Henderson was familiar with the doctrine of the internal environment throughhis training in medicine, he did not make use of it at this time. 37. Ibid., pp. 166, 172-173. 38. L. J. Henderson, "A Critical Study of the Process of Acid Excretion," J. Biol. Chem., 9 (1911), 403. 39. See E. F. Adolph, "Early Concepts of Physiological Regulations," Physiol. Rev., 41 (1961), 737-770; Holmes, "Claude Bernard's Concept," pp. 172-174. 40. Holmes, "ClaudeBernard'sConcept,"pp. 195-198.

72

Organismic and Holistic Concepts of L. J. Henderson In this same paper, Henderson's continued wonder at the apparent fitness of certain substances for physiological processes is reflected in the following paragraph: It would be difficult indeed to account for this remarkable coincidence, that phosphoric acid, one of the chief excretory products of the urine, possesses the very highest possible efficiency in the physiological process for regulating the ratio of acids to bases in the body fluids by means of renal activity. Certainly there seems to be nothing in evolutionary theory to explain it, and for the present it must be considered a happy chance, like the fact that the maximum density of water falls at 40, and several other logically similar circumstances.41 This quotation indicates that Henderson had recognized by this time that water also displays a certain "fitness." In addition, it was becoming clear to him that natural selection could not explain certain facts to his satisfaction. Was it just an accident that the products of the metabolism of carbon and phosphorous compounds, namely carbon dioxide and phosphate, possessed simultaneously a number of different properties which were important in various physiological processes? 42 It was not until February 1912, however, that he realized the reciprocal nature of biological fitness. The idea came to him quite unexpectedly, he later explained, during a walk: . . . I saw that fitness is a reciprocal relation, that adaptations in the Darwinian sense must be adaptations to something, and that complexity, stability, and intensity and diversity of metabolism in organisms could not have resulted through adaptation unless there were some sort of pattern in the properties of the environment that, as I now partly knew, is both intricate and highly singular.43 He then quickly set to work upon The Fitness of the Environment, where he posed the problem: To what extent are the properties of the inorganic environment favorable to the existence of organisms, and, if they are highly favorable to life, can such "fitness" be considered accidental? 44 To simplify the problem, he focused on carbon dioxide, water, and the carbon compounds, which he felt were the key constituents of the 41. Henderson, "Acid Excretion," p. 417. 42. Henderson indicates in his "Memories,"p. 177, that such questions bothered him at this time. 43. Ibid., p. 180. 44. Henderson, Fitness, p. 37.

73

JOHN PARASCANDOLA

environment as far as life was concerned.45Using data from the literature, he comparedthe propertiesof carbon, hydrogen, oxygen, and their compounds to those of numerous other substances. He found that these three elements and their compounds possessed unique (i.e. maximum, minimum, or anomalous) values for many important properties. In general, these values were uniquely favorable for promoting the complex, varied, and stable mechanisms necessary to life. This led him to conclude that the actual environment is really "the best of all possible environments for life."48 He argued further that: There is, in truth, not one chance in countless millions of millions that the many unique properties of carbon, hydrogen,

and oxygen, and especially of their stable compounds water and carbonic acid, which chiefly make up the atmosphereof a new planet, should simultaneously occur in the three elements otherwise than through the operationof a natural law which somehow connects them together. There is no greater probability that these unique properties should be without due cause uniquely favorable to the organic mechanism. These are no mere accidents; an explanation is to seek. It must be admitted,however, that no explanation is at hand.47 Natural selection, for example, will not explain the fitness of the environmentfor life in general, for this fitness precedes the existence of life. It is a result of the properties of matter and energy and the course of cosmic evolution.48Cosmic and biological evolution thus seemed to be somehow linked, Henderson suggested, forming a single, orderlyprocess.49Although he did not rule out the possibility of the existence of some unknown mechanistic explanation for this connection, he stressed that it was difficult to conceive of one.50It was also conceivable,he added,that a teleologicaltendencyexisted which worked in parallel with mechanism without interfering with it. Although admitting that this was a metaphysical rather than a scientific doctrine, he attempted to remove some of the objections to this view and remarked that it had strong claims to sympatheticregardfrom men of science.5' It should be made clear that Henderson,who was an agnostic, did not draw any religious or theological conclusions from his consideration of fitness. He seemed to see this "teleological principle"as an inherent propertyof matter and energy: "Mat45. Ibid., pp. 61-63. 48. Ibid., pp. 274-275. 50. Ibid., pp. 305-306.

74

46. Ibid., p. 273. 47. Ibid., p. 276. 49. Ibid., pp. 278-279. 51. Ibid., pp. 306-308.

Organismicand Holistic Conceptsof L. J. Henderson ter and energy have an orginal property, assuredly not by chance, which organizes the universe in space and time."52 The question of fitness continued to occupy a prominent place in his thought for the next few years. Although he had concluded that no scientific explanation of this phenomenon appeared possible, he was constantly teased into looking for one. He was willing to consider any hypothesis, no matter how absurd it seemed.53In his desire to shed light on the subject, he was led to do an enormous amount of reading in the literatureof teleologyand natural theology.54 Within a year or so after the publication of The Fitness of the Environment, it occurred to Henderson that he could improve and generalize his case by utilizing Willard Gibbs'sconception of a physicochemical system.55In The Orderof Nature (1917), he undertookto show that the propertiesof matter and energy are ideally suited for the evolution of physicochemical systems in general, not just living organisms. In this book, he also "venturedto sketch the development of thought upon the problem of teleology, and at length to confront the scientffic conclusions with the results of philosophical thought, in order 56 finally to attempta reconciliation." Henderson noted that Gibbs had established that the world of physical chemistry is made up of systems. The concept of an independent system is an abstraction, of course, since no material system can really be perfectly isolated. It is an abstraction which the scientist needs, however, in order to deal with physical structure and chemical composition, just as he needs the abstract concept of mass, independent of all other forces than gravitation,in his study of dynamics.57 The data collected in The Fitness of the Environment was

reviewed again, and the conclusion was reached that the properties of hydrogen, carbon, and oxygen (and their compounds) are uniquelyfavorableto the existence of a diversityof complex, stable systems which exhibit a variety of activities.58Henderson stated that:

The process of evolution consists in increase of diversity of systems and their activities, in the multiplication of physical occurrences,or, briefly,in the productionof much from little. 52. Ibid., p. 308. 53. Henderson, "Memories," pp. 199-201. 54. Ibid., pp. 203-205. 55. Ibid., pp. 206-208. 56. L. J. Henderson, The Order of Nature: An Essay Mass.: Harvard University Press, 1917), p. 8. 57. Ibid., pp. 125-127. 58. Ibid., pp. 155-185.

(Cambridge,

75

JOHN PARASCANDOLA

Other things being equal there is a maximum "freedom"for such evolution on account of a certain unique arrangement of uniquepropertiesof matter.659 Even if one could explain the coincidence of these properties as being due to some simple cause, e.g. in terms of electrons, this would still not explain why "each and all of these unique properties should be favorable to the production of systems." For, Henderson argued, the characteristicsof systems and the properties of matter are independent of each other. They are both absolute properties of the universe, changeless in time, and one cannot conceive of any mechanical interactionbetween them. Yet there is an adaptationbetween the propertiesof matter and the diversity of evolution, and the probabilitythat this is due to chance would seem to be infinitely small. The pattern of properties exhibited by the elements appears to be in some sense a preparationfor the processof evolution.60 was sciHendersonhad to admit that the term "preparation" entifically unintelligible. He used the word "teleological"to describe this adaptation because there was no other word to describe it. But he stressed that he did not mean to imply that it was due to design or purpose. "Teleology"appears rather to have represented order or "harmoniousunity" to Henderson.6l There seemed to be no escape, he believed, from the conclusion of Bernard Bosanquet, the English metaphysician, that nature must be regarded from the viewpoints of both teleology and mechanism, that is, as an individual whole and as constituted of interactingmembers.62Hendersonconcluded: Nothimg more remais

but to admit that the riddle surpasses

us and to conclude that the contrast of mechanism with teleology is the very foundation of the order of nature, which must ever be regarded from two complementary points of view, as a vast assemblage of changing systems, and as an harmonious unity of changeless laws and qualities working together in the process of evolution.63

This point of view is an elaborationof his earlier suggestion that a "teleologicaltendency"exists, operating in parallel with mechanism. He was obviously influenced by Bosanquet'spaper of 1906 on teleology, which expressed the views cited in The Order of Nature. It seems probable that Henderson read this paper in 1915, for a letter indicates that he borrowed a copy 59. Ibid., p. 191. 61. Ibid., pp. 204-206.

76

60. Ibid., pp. 189-190,201-203,209-211. 63. Ibid., p. 206. 62. Ibid., pp. 112-115.

Organismicand Holistic Conceptsof L. J. Henderson of it from R. F. A. Hoernle in that year.04 Hoernle, who had workedunder Bosanquetfor three years, had joined the Philosophy Departmentfaculty at Harvardin the previousyear. We must analyze this dualistic conception of nature more closely, for it is important to Henderson's view of biologlcal organization and it represents a change from his earlier "naive realism." At this time, he still maintained that the world of our senses, of experience, was a world of matter, energy, space and time.f65Although he was aware that our ideas of these concepts undergochange, he felt that: . . .we can scarcely think that our present ideas are inadequate for our present purposes, or that, for life, matter will ever be other than the elements of the periodic classification, energy that set of quantities to which we apply the laws of thermodynamics, and time and space the concepts which were familiar to Galileoand Euclid.66

In this manner he justified ignoring, for example, the principle of relativity in his discussions of fitness and order.67The world, he argued, is made up of individual systems, consisting of matter and energy.68When we wish to do more than just describe individual phenomena, however-that is, when we wish to generalize-then we must take into account the laws of nature. These laws "depend upon our perceptions or judgments of the relations existing between things."69The law of gravitation, the law of conservation of energy, etc. "enable us to imagine the conditions under which aUlphenomena may be assumed to take place."70 They are rational in nature, i.e. the products of human reason, and not conceived to have objective existence. Henderson apparentlybelieved that the relationship which he had discoveredbetween the propertiesof carbon, hydrogen, and oxygen and the characteristicsof systems was of a similar nature.7' The peculiarities of these three elements are not the cause of anything in a mechanical sense. "They are merely the conditions under which the phenomena reveal themselves."72The relationship itself is is rational and nonmechanical, whereas the things related are mechanical and nonrational. 64. Letter from R. F. A. Hoernl6 to L. J. Henderson, May 2, 1915, Widener Library Archives, Harvard University. 65. Henderson, Fitness, pp. 8-21. 66. Ibid., p. 21. 67. Ibid. 68. L. J. Henderson, "Mechanism, from the Standpoint of Physical Science," Phil. Rev., 27 (1918), 576. 69. Henderson, Order, p. 195. 70. Ibid. 71. Ibid., p. 200. 72. Ibid., p. 199.

77

JOHN PARASCANDOLA

It is also teleological, because the properties of these elements seem to be in some way a preparation for the evolution of systems.78

We can also vaguely distinguish, he added, other teleological aspects among nature's laws, "i.e. among the general abstract characteristics of nature which may be exactly defined."For example, he believed that all systems exhibit a tendency toward a state of dynamic equilibrium, and he saw teleological implications in this phenomenon.74Mechansm thus seemed to him unable to account for everything. On the other hand, he did not see this fact as presenting any problemto the scientist. For the only place where mechanism failed was in explaining the origin of things, and he believed that at this point "thought had arrived at one of its natural frontiers."The existence of the universe, for example, is no concem of the scientist, for mechanism can never face the problem of the existence of matter and energy. He was also rather pessimistic about the possibility of the scientist ever explaining the origin of life. The problem of the origin of fitness was thus just one more inexplicable riddle of nature.71

It would appear that Henderson had unduly restricted the scope of the scientists' interest. For today the origin of life and the origin of the universe are the subjects of intensive research, and there are probablyfew scientists who would deny that they will eventually receive a scientific explanation, at least in part. The problem of the origin of matter and energy, however, may well present an impasse to human thought. George Wald has reminded us, however, that several major scientific upheavals have occurred since The Fitness of the Environmentwas written. The electronic theory of valence, wave mechanics, the concept of hydrogenbonds, and the theoryof chemicalresonance are only a few of the important developments which have greatly altered the outlook of science in the last half a century. Wald concludes: "Wehave learned many new things, and new ways to talk about old things. We can go further now with some of Henderson'squestions, and would now put differently some of the things he said. Some of his problemsare no longer pressing problems . . . Other matters that seemed particularly

obscure and unapproachable to Henderson now are pursued with the highest interest."76 73. Ibid., pp. 203-206.

74. Ibid., pp. 206-207.

75. Ibid., p. 209; Henderson, Fitness, pp. 308-310.

76. George Wald, "Introduction,"in L. J. Henderson, The Fitness of the Environment: An Inquiry into the Biological Significance of the Properties of MatteT(Boston: Beacon Press, 1958).

78

Organismicand Holistic Conceptsof L. J. Henderson What about the question of fitness? The first part of Henderson's dilemma, the fact that his three chosen elements and their compounds posess maximum, minimum, or anomalous values for so many different properties,has been cleared up to some extent. Many of the unique properties of water, such as its great surface tension, high boiling point, and high heat of vaporization, are now known to be due to its ability to form hydrogen bonds. Many of the special properties of hydrogen are due to its small size and its central position in the electronegativity scale.77 Yet although these facts may explain why certain properties occur simultaneously in an element or a compound, they cannot explain why all of these properties should be favorable to life (or to physicochemical systems in general). As George Wald has written: . . .carbon is good for making organisms in part because it forms multiple bonds; but what if it didn't? Suppose that carbon dioxide polymerizedto form rocks just as does silicon dioxide. Where would we be then-or would we be? It is an uncomfortable question. Out of the ninety-two natural elements, four-C, N, 0, and H-have unique propertiesthat make life possible. Suppose as one easily can, that they were less unique, more like the other elements. One wouldn'thave to go far in that directionto make life impossible.78 We need not take these facts as evidence for some kind of master plan in nature, however. The facts that Hendersoncites, argues J. D. Bernal, can just as well be taken "as evidence that life had to make do with what it had, for if it had failed to do so it would not be there at all." 79 Yet anyone reading these works by Henderson cannot help being impressed by the "fitness" of the materials which life was given to work with, even if this should just be due to chance. The most important and 77. For a discussion of the factors underlying some of the unique properties of these substances, see Wald, "Introduction"; Harold Blum, Time's Arrow and Evolution (Princeton University Press, 1951), pp. 73-86. 78. Wald, 'Introduction." It is interesting to note that Henderson underestimated the importance of nitrogen in biochemistry, just as he had earlier underestimated the role of the proteins as buffers. He wrote in a letter to E. V. Titchener, April 13, 1918 (Baker Library Archives, Harvard University): "I am much inclined to think that sulphur, phosphorous and the inorganic source [salts?] of protoplasm come a good deal nearer to nitrogen in importance than nitrogen does to carbon, hydrogen, and oxygen." Of course, at this time, the role of the nucleic acids in heredity and of nucleotides such as ATP in energy transformations were unknown, and the question of whether enzymes were proteins or not was still being debated. 79. J. D. Bernal, The Origin of Life (World: Cleveland, 1967), p. 169.

79

JOHN PARASCANDOrA

lasting contributionof these books is that they make clear the dependence of the existence and nature of life upon the environment. The inorganic world has placed certain restrictions upon the direction that organic evolution can take.80The realization of this fact has apparently led some biologists to conclude, in the words of George Wald, that "there can be no way of composing and constructing living organisms which is fundamentallydifferentfrom the one we know."8' Henderson'sinterest in the fitness of the environmentforced him to consider the nature of the organsm more carefully. In order to ask whether the environment is truly fit for life, he had to ask himself what the chief characteristicsof the lving organism were. For the purposes of his study, he settled on three: complexity,durability(or stability), and metabolism,i.e. the exchange of matter and energy with the environment.82 Life must also manifest itself as a physicochemicalmechanism. In The Order of Nature, he wrote:

Just because life must exist in the universe, just because the living thing must be made of matter in space and actuated by energy in time, it is conditioned. In so far as this is a physical and chemical world, life must manifest itself through more or less complicated, more or less durable physico-chemicalsystems.88 These ideas concerning the organism may have derivedfrom his work on the acid-basebalance, for a paragraphpreviously quoted from a paper of 1911 indicated that he recognized the need for stable conditions within the organism as well as for exchanges of matter and energy with the environment. At that time, it will be recalled, he did not associate the milieu int6rieur with this constancy of conditions.It was apparentlyhis speculations on fitness which promptedhim to utilize this concept for the first time, althoughhe may have been aware of its existence earlier. In The Fitness of the Environment, he pointed out

that the environment must provide a certain stability in order for organisms to survive. The ocean, for example, provides an excellent environment for life because such conditions as temperature, alkalinity, and ionic concentration are accurately regulated.84Of course, he was aware that warm-bloodedani80. Ibid., pp. 167-169; Wald, "Introduction";Blum, Time's Arrow, pp. 206-209. 81. George Wald, "The Origin of Life," Sci. Am., 191 (August 1954), no. 2,53. 82. Henderson, Fitness, pp. 30-35. 83. Henderson, Order,p. 6. 84. Henderson, Fitness, pp. 189-190.

80

Organismic and Holistic Concepts of L. J. Henderson mals are to a certain extent independent of the extermal environment, and it was in this connection that he first mentioned the milieu interieur. These animals, he noted, have acquired an environment of their own, a milieu int6rieur, which serves the same purpose as stability of the external environment.85 Henderson also suggested that the similarity between certain of the regulatory mechanisms of the blood and those of the ocean provides some evidence for Archibald Macallum's theory that the body fluids of animals consisted originally of sea water that had become enclosed.86 According to Holmes, Macallum's theory, expounded around the beginning of the twentieth century, quickly became influential and was often associated with the evolution of the internal environment.87 It is interesting that Henderson did not mention Claude Bernard's name in connection with the theory of the milieu intrieur. He did refer to him in The Fitness of the Environment, however, with regard to his concept of a "directive idea." He wanted to call attention to the fact that even physicochemical determinists like Bernard had suggested the possible existence of a nonphysical force in nature.88 Bernard spoke of this force in connection with the living being, however, while Henderson's "teleological tendency" operated in all of nature. In fact, the latter used this view as an argument against vitalism, for life was apparently not unique in exhibiting order or teleology.89 That the organism does possess a pattern, that it is an organized system, even if it was not unique in this respect, he did not doubt. We have already seen that Henderson recognized the interrelation between certain physiological processes and the importance of the regulation of conditions within the organism. In 1913 he wrote that "it is gradually becoming clear that all the physicochemical conditions in protoplasm-alka85. Ibid., pp. 32-33, 186.

86. Ibid., pp. 186-189; L. J. Henderson, "The Regulation of Neutrality in the Animal Body," Science, 37 (1913), 391. 87. Holmes, "ClaudeBernard'sConcept,"pp. 226-230. 88. Henderson, Fitness, pp. 286-287, 306. Holmes has pointed out ("Claude Bernard's Concept," pp. 239-244) that the English physiologist Ernest Starling incorporated the concept of the "internal medium" into his 1908 lectures on the body fluids without mentioning Bernard's name. Holmes suggests that the idea was possibly becoming a part of the common thought and language of the physiology of the time. This view is supported by the fact that Charles Sherrington also mentioned the internal environment in 1906 without referring to Bernard. He spoke instead of "that which French physiologists term the milieu interne." See his The Integrative Action of the Nervous System (New York: Charles

Scribner'sSons, 1906), p. 4. 89. Henderson, Fitness, pp. 299-300.

81

JOHN PARASCANDOLA

Uinity, osmotic pressure, colloidal swelling, chemical equili90 He called attenbrium, temperature-are interdependent." tion to Cuvier'sanalogy comparing life to a vortex, with molecules continually entering and leaving, but the form remaining. This view seemed to him, however, to be a justificationfor the study of physiochemical conditions, of dynaic equilibria, rather than of morphological elements. "What indeed is the importance of the anatomy of a whirlpool in comparisonwith the dynamicsthereof?"91 His studies on acidosis, particularly those in collaboration with Walter Palmer92during the period from 1913 through 1915, led him deeper into the realm of biological problems.He found himself, for the first time, "facing the kind of complications that are characteristicof biological as distinguishedfrom chemical phenomena."The investigation of acidosis was instrumental in forcing him to study biological literature and methods, and he began to think of himself as a physiologist rather than a biochemist.93This first venture into clinical studies greatly influenced his thinking. He wrote in his 'Memories": This was the first time that I ever frequented a hospital

and, although I hardly went outside the laboratory,I did become familiar with the atnosphere of a hospital and with the point of view of clinicians. For the first time I was closely associated with men who hourly bear a heavy responsibility for their decisions and actions. This, although I was at first unaware of it, modified, and in the end greatly modified,my point of view. This evolution of my point of view I cannot trace during these early years, but it seems to me almost certain that my associationwith Palmer was the beginning of a change that in the end became great. There is, however, one aspect of the change that I venture to set down because it seems to correspond to a clear recol-

lection. Somewhere about this time I began to feel that kind of pleasure in the recognition of the concrete phenomena of the clinic that I had altogethermissed as a medical student. There is both in understandingand in feeling a great differ90. Henderson, "Regulationof Neutrality," p. 389. 91. Ibid. 92. Walter W. Palmer (1882-1950), who received his M.D. at Harvard in 1910, was a resident physician at the Massachusetts General Hospital from 1913 to 1915. He later went on to a disinguished career as professor of medicine at Columbia University, and made significant contributions to our understanding of diabetes and thyroid physiology. 93. Henderson, "Memories,"pp. 135-136; the quotation is from p. 135.

82

Organismicand Holistic Conceptsof L. J. Henderson ence between the larger generalizations of physical science, on the one hand, and the endlessly varying complexity of the states and conditions of the living organism, on the other hand. This is, on the whole, the difference that in the past, since the beginnlingsof modem science, has most strikingly distinguished physics from natural history. I had grown up with interest like those of the physicists and with the absurd feeling, so common among physical scientists, that the generalizations of physics are somehow superior to other scientific knowledge.I now began to realize the pleasure of understanding and the interest of the complex, concrete event, and I soon learned how far short of an effective description the simple applicationsof generallaws may be.94 These studies further increased his awareness of the complexity of the organism. In the course of this work, Henderson and Palmer made several importantcontributionsto our knowledge of acidosis. They helped to call attention to the frequent occurrence of acidosis in various pathological conditions.95 Along with other investigators, they showed that acid intoxication does not always involve the presence of acetoacetic and p-hydroxybutyricacids in the urine. Almost simultaneously with Andrew Sellards of Johns Hopkins, they suggested a new definition of acidosis as a decrease in the bicarbonate concentration of the blood, along with a simple test to detect the condition.98This definition is still the accepted one for the condition known as "metabolicacidosis,"in which acid intoxication results from metabolic reactions. It is now known, however, that there are cases where the bicarbonate level of the blood drops but its pH actually increases-in other words, 94. Ibid., pp. 223-224. 95. See, for example, L. J. Henderson, L. H. Newburg, and W. W. Palmer, "A Study of the Hydrogen Ion Concentration of the Urine in Heart Disease," Arch. Int. Med., 12 (1913), 146-152; L. J. Henderson and W. W. Palmer, "On the Several Factors of Acid Excretion in Nephritis," Arch. Int. Med., 16 (1915), 109-131. The term "acidosis" is somewhat misleading. The condition is not associated with any real acidity of the blood, because the pH of the blood never drops below 7.0 except perhaps in diabetic coma. 96. L. J. Henderson and W. W. Palmer, "Clinical Studies on Acid-Base Equilibrium and the Nature of Acidosis," Arch. Int. Med., 12 (1913), 153-170; A. W. Sellards, "The Determination of the Equilibrium in the Human Body between Acids and Bases with Especial Reference to Acidosis and Nephropathies," Bull. Johns Hopkins Hosp., 23 (1912), 289302; A. W. Sellards, "The Essential Features of Acidosis and their Occurrence in Chronic Renal Disease," Bull. John Hopkins Hosp., 25 (1914), 141-153.

83

JOEHNPARASCANDOLA

becomes more alkaline-and this situation is overlookedby the abovedefinition.97 Although Hendersonhad recognized the interrelationof various bodily processes and the importance of self-regulationwell before 1915, he did not specifically discuss the concept of biological organization until that year. It appears that J. S. Haldane'sview of organization,as expressed in his Mechanism, Life, and Personality (1914), promptedHendersonto consider this concept, for his first treatment of the subject appearedin a review of Haldane's book. Haldane severely criticized the mechanistic theory of life, labeling it a failure, but could not accept vitalism as a satisfactory alternative. He stressed the need to consider the organism as an organized whole.98Henderson acknowledgedthe fact that mechanists generally overlooked the significance of organization, and he thought "that Haldane is quite right in establishing organizationas something of a different order from mechanism, and elevating it into a category."99 He criticized Haldane's idealist metaphysics, however, arguing that the physiologist need not concern himself with the problem of "reality."In addition, he felt that while there may be no one ultimate mechanism of life, there are mechanisms which make up the organism. He concluded that: The truth seems to be that the relation of an organism to cellular mechanisms is not unlike the relation of a symphony to the sound waves which bear it to the ear. It is absurd to regard the symphony as merely the sum of the waves of sound, just as it is absurd to regard the organism as merely the sum of the biophysical and biochemical phenomena. But it is quite as absurd to deny that the sound waves are in a 97. Such a condition can occur by hyperventilation of the lungs, e.g. by a forced rapid rate of breathing, causing the Co, content of the blood to drop. The bicarbonate concentration of the blood will also decrease in an attempt to maintain the HCOa/NaHCOaratio constant, but if it does not completely compensate for the CO, loss, the pH wil go up. This condition has often been called "gaseous" or "respiratoryalkalosis," although it involves a reduction in the plasma bicarbonate. On the other hand, if the excretion of CO, is hindered, as in pneumonia, the carbonic acid content of the blood rises and this may not be balanced by a proportional rise in bicarbonate. The pH is then lowered and the condition referred to as "respiratory acidosis," in spite of the fact that the bicarbonate concentration has increased. See C. H. Best and N. B. Taylor, The Physiological Basis of Medical Practice (Baltimore: Williams and Wilkins, 1961), pp. 132-133. 98. J. S. Haldane, Mechanism, Life and Personality: An Examination of the Mechanistic Theory of Life and Mind (London: J. Murray, 1914). 99. L. J. Henderson, review of J. S. Haldane's "Mechanism, Life and Personality," Science, 42 (1915), 381.

84

Organismicand Holistic Conceptsof L. J. Henderson veryreal sense (even if they are not in "reality")the component parts of the symphony. They are, moreover, the only component parts which at present can be profitablyinvestigated, as the differencebetween the substantialcharacterof musical science and our vague ideas about the individuality of thematic material well shows. If we turn to Haldane's own experimentalresearcheswe shall find that that is preciselyhis own standpoint as a practical physiologist; he analyzes the phenomena of organizationinto their componentphysical and chemical parts."100 Henderson further developed his own position on biological organizationin The Orderof Nature and in several papers during the period from 1917 to 1920. He did not see the concepts of mechanism and organization as being mutually exclusive. In his view, "the fact of organizationis insufficientto overthrow the mechanistic hypothesis, although it must be admitted that a mechanistic philosophy which leaves organization out is meaningless."101The structures and processes of the organism, which are the things that are organized, are themselves mechanical, "'butlike the idea of beauty, the idea of organization is in no sense a mechanical concept."102 He commented that: "What we need to know and always to remember is that organizationqualifiesthe body mechanisms. They are mechanisms and also they are organized."103 This dualistic approach,contrastingorganizationwith mechanism, reminds one of Henderson'sview of nature. In fact, he specifically noted that biological organization,like the relationship between the properties of matter and the characteristics of systems, is a rational, nonmechanical and teleological relationship.104The concept of organizationexpresses a functional relationship. The organism is "an autonomous unit in which every part is functionally related to every other and exists as

the servant of the whole."'0O Organization, like the second law of thermodnyamics,is a condition of the physicochemical phenomenaof life.'06 What were the consequences of this philosophical view of organization for Henderson as a working physiologist? In the 100. 101. p. 576. 102. 103. 104. 105. 106.

Ibid., p. 382. Henderson, "Mechanism, from the Standpoint of Physical Science," Henderson, Order, p. 70. L. J. Henderson, "Acidosis," Science, 46 (1917), 77. Henderson, Order, p. 205. Ibid., p. 21. Henderson, "Acidosis," p. 75.

85

JOHN PARASCANDOLA

first place, he became more convinced than ever of the importance of studying the regulatoryprocesses of the body. For he felt that as far as the physiologistis concerned,the investigation of biological organization basically means the elucidation of these regulatoryprocesses.107On the one hand, they are physicocheniical processes which can be studied by physicochemical techniques, and, on the other hand, they are illustrationsof the phenomenon of organization.108The regulatory mechanisms compensate for changes which disturb the organizationof the body; they act to preserve the state of dynamic equilibrium which is essential to life.'09 As we shall see, he later came to view Bernard'stheory of the regulation of the milieu int6rieur as an importantand concrete example of organization.In 1917, however, this theory still did not play a significant role in his thinking, for he cited Bernard as an advocate of the idea of organzation without even mentioning the internal environment."10Yet there was a definite connection in his mind between the concepts of organizationand regulation, as is further illustrated by a comparison of two passages from his writings, the first dating from 1914 and the second from 1917: [1.] The history of this problem of regulation is lost in antiquity. Aristotle saw it clearly. Few great biologists since him have escaped it. Yet I think that little progress towards its final mastery has been made, and only recent scientdfic researches put the subject on the sound basis of experiment. In general biology the modem definition seems to derive, strange to say, from Herbert Spencer. His famous "Conception of Life" as "the continuous adjustment of internal relations to external relations" is indeed vague. But when one falls back upon the analytical discussions from which Spencer arrivedat it, I think one may truly say that the "Conception" comes to little else than a question of equilibnrum, involving the totalityof organicrelations."' [2.] This conclusion points straightback to Aristotle,whose great attainments as a zoologist together with his extreme virtuosity in conceiving and applying abstract ideas and for107. Ibid., p. 77; Henderson, Order, p. 82. 108. L. J. Henderson, "Acidosis and the Physicochemical Equilibrium of the Organism," in H. A. Christian, ed., Oxford Medicine (New York: Oxford University Press, 1920), I, 306. 109. Henderson, "Acidosis," p. 77, and Order, pp. 83-84. 110. Henderson, "Acidosis," pp. 74-75, and Order, pp. 76-77.

111. L. J. Henderson, "The Excretion of Acid In Health and Disease," The Harvey Lectures, 10 (1914), 132. See Herbert Spencer, The Principles of Biology (New York: D. Appleton, 1888), I, 80.

86

Organismicand Holistic Conceptsof L. J. Henderson mulas led him to an analysis of organization that remained the best for more than two thousandyears . . . . . . The earlier modem biologists are also inferior to Aristotle,for when they have perceivedthe riddle of organization, it has led them into sterile vitalistic theories or mere bewilderment. But during the last century there took place a steady improvement in biological analysis and lately the subject has been partly cleared of misunderstanding,so that it is today in the minds of most thoughtful investigators . . . . . . It is now possible to see that Herbert Spencer's conception of life as "the continuous adjustment of internal relations to extemal relations," though doubtless far from satisfactory as a characterizationof life itself, is really a true statement of the phenomenonof organization.112 Henderson thus came to use essentially the same words in referring to organization that he had employed earlier with regard to regulation. He also pointed out that the study of organizationhad recently become a major goal of physiological research, as exemplified by research on regulatoryphenomena such as hormones, the integrative action of the nervous system (Sherrington), and emotional excitement (Cannon).113As far as he was concerned, the "intemal teleology"of the organism was really nothing more than self-regulation.114 In addition, Hendersonbelieved that the concept of organization taught the biologist to recognize the wholeness of the organism and the interdependenceof its parts and processes. In studying a pathological condition like acidosis, for example, one must realize: . . . that there is no one process or phenomenon which is the fundamental or essential one, but that each is integral, at once as cause and as effect in a cycle of pathological changes whose onset may be at any one of many points and which as a whole, as a cycle, constitutes the deranged acidbase metabolism. But this, moreover,is not the whole of the matter, for, just as the parts of this cycle engage in the whole of the process of acid-basemetabolism,so do they also engage, as parts, in other processes, some of them in the respiration, some in the process of excretion, and so on indefinitely.Thus the condition known as acidosis can only be truly conceived 112. Henderson, "Acidosis,"pp. 74, 77. 113. Ibid., pp. 76-77, and Order, pp. 80, 83. Cannon had not yet developed his ideas on homeostasis nor had he made use of Bernard's theory at this time. 114. Henderson, Order,p. 84.

87

JOHN PARASCANDOLA

of in terms of the organization of the body as a whole.115 This emphasis on the mutual dependence of the variables in a system, and on the limitations of cause and effect analysis, played an important part in his researches on blood, to which we must now turn. Henderson'sresearches on neutralityregulation and acidosis had caused him to familiarize himself, to some extent, with the literature on blood. He was well aware of the important discovery of Bohr, Hasselbalch, and Kroghin 1904 that the oxygenation of hemoglobin varies inversely with the carbon dioxide pressure of blood."18This fact is of great biological significance, for it means that in the tissues, where the C02 pressure is high, the dissociation of oxyhemoglobin to release oxygen is facilitated. Moreover, the loss of C02 from the blood in the lungs promotes the combination of oxygen with hemoglobin. It should have been obvious, Henderson later argued, that if carbon dioxide affects the oxygen dissociation curve, then oxygen must affect the carbon dioxide dissociation curve.17 He wrote in his "Memories": Even schoolboys are taught that if Y is a function of X, X is a function of Y, and that is all the argument that is necessary in the premises. Bohr, Hasselbalch and Krogh did investigate this question, but probablyon account of the inadequacy of their experimentalmethods, failed to discoverwhat they were looking for and gave up the attempt. Thereafter, until 1913, all the physiologists who were interested in the subject, including, besides the Danish investigators, J. S. Haldane, Barcroft, A. V. Hill, and others, failed to notice this simple inference, and so did I.118 It was actually in 1914 that Christiansen,Douglas, and Haldane reported their experimental discovery that oxygen does indeed affect the equilibrium between carbon dioxide and blood."19According to Henderson, however, Haldane revealed to him that he had not been led to this investigation by reason115. Henderson, "Acidosis,"p. 77. 116. Christian Bohr, K. A. Hasselbalch, and August Krogh, "Ueber eilnen in biologischer Beziehung wichtigen Einfluss, den die Kohlensfurespannung des Blutes auf dessen Saurestoffbindung ubt," Skand. Arch. Physiol., 16 (1904), 401-412. 117. L. J. Henderson,

Blood: A Study in General Physiology

(New

Haven: Yale University Press, 1928), pp. 79481; Henderson, "Memories," pp. 157-160. 118. Henderson, "Memories,"p. 158. 119. Johannes Christiansen, C. G. Douglas, and J. S. Haldane, 'The Absorption and Dissociation of Carbon Dioxide by Blood," J. Physiol., 48 (1914), 244-271.

88

Organismic and Holistic Concepts of L. J. Henderson ing from the phenomenon discovered by Bohr and his colleagues.120 Henderson later stated that this discovery by Haldane and his coworkers led him to conclude "that every one of the variables involved in the respiratory changes of blood must be a mathematical function of all the others." 121 We have already seen that by 1913 he had become aware of the high degree of interdependence between bodily functions, and this realization no doubt also influenced his conclusion about the interrelation of variables in blood. At the time, Henderson was preoccupied with other problems, and he later became engaged in war work involving the physical chemistry of breadmaking. Therefore, he did not return to the question of the interrelations between the components of blood until 1919. The only motive which he could later recall for attacking this subject at that particular time was a feeling of guilt because he thought that he had not begun any new significant work during the war years.122 In a theoretical paper dealing with the equilibrium between carbonic acid and oxygen in blood, he derived from available experimental data an equation which expressed the following relationship between four of the components of blood: (CO2) 0.014(02)2.5

+ 7.7

(Hb) (HbO2)

where Hb represents reduced hemoglobin and HbO2 represents oxyhemoglobin. On examining this equation, he wrote: . . . it is evident, from general thermodynamical principles, since increasing the concentration of carbon dioxide results in an increase of the concentration of oxygen, that increasing the tension of oxygen must likewise increase the tension of carbon dioxide. This conclusion, as far as I can see, could fail only in case there were present something resembling a rachet mechanism, by which the carbon dioxide could act upon the oxygen without the possibility of a corresponding reaction. But such mechanisms are at present unknown in physicochemical systems.123 120. Henderson, "Memories," p. 160. 121. Henderson, Blood, pp. 95-96; the quotation is from p. 96. In his "Memories," p. 160, Henderson claims that he had actually realized on his own, shortly before Haldane's paper appeared, that oxygen must necessarily influence the carbon dioxide dissociation curve of blood. 122. Henderson, "Memories," pp. 243-244. 123. L. J. Henderson, "The Equilibrium between Oxygen and Carbonic Acid in Blood,"' J. Biol. Chem., 41 (1920), 403.

89

JOEN PARASCANDOLA

In any case, he added, Haldane and his coworkershad already proved experimentally that oxygen does influence the CO2tension in blood in this manner.L24Henderson was essentially indicating here only that this fact could have been predicted by theoretical means even before it was discovered experimentally.In this paper, he also brieflydiscussed some other examples of the interaction between the components of blood, such as the increase in volume of the corpuscleswhen carbonic acid tension increased.125In referring to this article years later, he wrote: . . .this marks quite unmistakablya first step in this kind Of work that I was to continue to do for a number of years. . . . and it seemed to me that this unimportantpiece of work is one thing as a contributionto science and an entirely different thing as a bit of my own experience considered in its relations to what had gone before me and what was to come after, and especially as a part of the pattern of my continuing experience.'26 He was probably being unduly modest about this piece of work, especially since the paper contains a remarkablededuction of the shift in pK of hemoglobin upon oxygenation. By this time, several investigators had already pointed out that oxyhemoglobin must be a stronger acid than reduced hemoglobin. Using the data of Christiansen,Douglas, and Haldane, Hendersoncalculated that the dissociationconstants of the acid radical of hemoglobin which increases in strength when oxyhemoglobin is formed should be about 2.3 X 10 8 (reduced form) and 2.0 X 10-7 (oxygenated form).'27 These figures correspond to pK values of 7.64 and 6.70, representinga shift of 0.94 pK units. The experimentalinvestigations of German and Wyman later measured the actual pK values of the oxygenlinked acid group of hemoglobin to be 7.93 and 6.68 respectively (representing a shift of 1.25 pK units).128This change in acid strength is physiologically important, as Henderson recognized, because it allows hemoglobin to combine with and

transporta considerableamount of carbon dioxide (in the forn of bicarbonate) without significantly altering the pH of the 124. Ibid., p. 404. 125. Ibid., p. 428. 126. Henderson, "Memories,"p. 245. 127. Henderson, "Equilibrium between Oxygen and Carbonic Acid," pp. 404 410. 128. See E. S. West and W. R. Todd, Textbook of Biochemistry, 3rd ed. (New York: Macmillan, 1961), p. 544.

90

Organismicand Holistic Conceptsof L. J. Henderson blood. At this point, Henderson realized that he had previously underestimated the contribution of proteins to the buffer capacity of the blood, mainly because the shift in acid strength of hemoglobin upon oxygenation was not known when he did his earlierwork.129 The real importanceof this paper for our purposes,however, is that it marks the beginning of his investigation of the interactions between the various components of blood. When Franklin McLeancame to work with him in the fall of 1919, Henderson suggested that he study the influence of oxygen on the distributionof chlorides between the corpuscles and plasma of blood. Since carbon dioxide was known to affect the chloride equilibrium,and since oxygen and carbon dioxide so profoundly affected one anotherin blood, Hendersonconcluded that oxygen must then also affect this equilibrium.130By this time, as previously noted, he was convinced that variation of any one of the variables in blood cannot occur without a variation in all the others. Experimental data were collected on the relations between oxygen tension, carbon dioxide tension, and the distributionof chlorides. The problem thus automatically arose as to how to describe the interrelations between a number of variables.131 Henderson described his struggle to find a successful solution to the problemas follows: . . . I found myself trying all sorts of graphical devices without plan and often hardly knowing what it was that I was doing. Then one day things began to fall into place, though I was hardly aware of how they were doing it, and presently I had under my hand a Cartesiannomogramwhich gave a complete representation of all the data. This was something differentthan anything that I had seen before, and at first I hardly understood it though in principle nothing could be much simpler. But I found that it worked to give any information that was directly implicit in the data, and after using it for a few hours it became clear to me that I had a very powerful tool. So, filled with curiosity and not a little delighted, because I had a half-intuitive realization that I had at last taken a step in advance in the synthetic treatment of the blood, I went to E. B. Wilson at Technology, showed him my figure, and asked him to tell me what it was. 129. Henderson, "Equilibrium between Oxygen and Carbonic Acid," pp. 410-413,423-428. 130. Henderson, "Memories," pp. 245-246. 131. Ibid., pp. 247-249.

91

JOHN PARASCANDOLA

When he said, '"Why,it's a nomogram,"I was obliged to reply, '`Whatis that?",for I had never heard the word.132 In 1920 he presented the nomographic work for the first time at the Physiological Congress in Paris. In the next year, the first of his series of papers on 'Blood as a Physicochemical System" appeared in the Journal of Biological Chemistry.183 In all, ten papers were published by Henderson and his coworkersunder this general title in the periodfrom 1921 to 1931. Most of these results were summarized in his classic book, Blood, A Study in General Physiology (1928). Most of the experimental work for these studies was performedin the laboratories of the Massachusetts General Hospital, with Arlie V. Bock and David B. Dill making the most significant contributions. Some of the researches were also done in collaboration with the workersin the laboratoryof Henderson'sfriend, Donald D. Van Slyke, at the Rockefeller Institute. As Joseph Barcroft noted: To such a mind as Henderson's,it was possible to treat of this great field without acquiring any mastery of the precise experimental techniques by which the data were obtained. It sufficed for him if the data which he plotted were reliable. He therefore, in collaboration with Van Slyke, organized a large circle of extremely able experimenters, some in New York,some in Boston, and some farther afield,who undertook the necessary analyses.134

With the aid of the nomogram, he presented a synthetic treatment of blood. He pointed out that one can be misled by considering equations which only include a few of the components of blood. For example, his own buffer equation expressed the interrelationsbetween hydrogen ion concentration, carbonic acid, and bicarbonate.The concentration of carbonic acid in blood, however, also depends upon other factors such as the oxygen tension, and hence we cannot neglect these other variables.135In general, there is a high degree of mutual de132. Ibid., pp. 249-250. 133. L. J. Henderson, "Blood as a Physicochemical System," J. Biol. Chem., 46 (1921), 411-419. 134. Joseph Barcroft, obituary of L. J. Henderson, Nature, 149 (1942), 375. 135. L. 3. Henderson, "Blood and Circulation from the Standpoint of Physical Chemistry," in H. H. Dale, J. C. Drummond, L J. Henderson, and A. V. Hill, Lectures on Certain Aspects of Biochemistry (London: University of London Press, 1926), pp. 201-204; Henderson, Blood, pp. 119-120.

92

Organismicand Holistic Conceptsof L. J. Henderson pendence between the components of blood or of protoplasm. As Hendersonexpressedit: Perhaps it may be said that protoplasm is characterized by a quantitativelylarge dependence of each variable on all the others, or on an improbablylarge proportionof the others and in an imnprobably large number of different modes. Certain it is that one of the most important peculiarities of protoplasmis the high degree of connection (or low degree of independence) between its components. But it should be noted that this is true of every well-integrated whole, for example, an atom, a molecule, or a watch. In protoplasm this principle of the high degree of connection between the parts is illustratedboth by phenomena at the level of simple chemical equilibrium,like the instance of the interaction of oxygen and carbon dioxide through hemoglobin above cited, and also by the structuralorganizationas revealed in studies of the mechanism of oxidization, of enzyme complexes, and the like.138 The nomogram allowed him to give a synthetic treatment of blood, to depict simultaneouslyall of the seven variables which he came to feel were necessary to describe the respiratorycycle. In his book on blood, he began with five experimentally determined equations involving these variables, with each equation expressed in terms of two independent variables, free oxygen (PO2) and free carbon dioxide (pCO2).137 A two-dimensional graph can be plotted for each of these equations, and these graphs can be combined into one figure. As Henderson noted, "two or more contour charts, provided they have the same Cartesian coordinates, may be combined, just as a geological map may be superimposedon a topographicalmap, following that if desired with a political map, an ethnographical map, and so on indefinitely."'38Each point on the complete nomogram has seven coordinates,so that if one knows the values of any two variables, the values of the other five can be read off the graph. The large number of lines present, however, makes such a chart difficult to read. This is illustrated by Figure 1, which is a reproduction of Henderson's original nomogram, first published in 1921. The variables chosen, six in all, are somewhat different from those which he later used. By the use of a simple 136. Henderson, Blood, p. 11. 137. For Henderson's description 115-152. 138. Ibid., pp. 121-122.

of the nomogram,

see ibid.,

pp.

93

JOHN PARASCANDOLA

Mpwl

202 -

-

3

(Nm.

103 ]AN1044

a1*~~~~~~~~~CI1046

/

tACMLk?~~~~104

g:gt

/812C01i

--o125 0013

--lZ

i 9 2!t@4; >02

j

/

03">/

&/92t

0

4\

/0 107.40

I

[og

"0,,,s,~~~~~~~~~~61

/0135 .OOI4 .001454DClSDOl55

01]1048

207.

30%*h0J1

/iel

40

0/

Al

50'LgioJ

/~~ 7.4

7.7-T5M "'0011058

1

79

721

5

,, 74/4V47 7.9

p

1~~~~~~~~~~~~~~~1058

/

807.

\X

'4

4 A 3

100'~~~~O140013D01Y.1503~055.0014

\0015

D

7015 [z4 Mpsl

Figure 1. Cartesian Nomogram for Mammalian Blood (From L. J. Henderson, Blood: A Study in General Physiology, Yale University Press, New Haven, 1928, p. 98. With the permission of the publisher.)

94

Organismicand Holistic Conceptsof L. J. Henderson

65 74 .618

61

0

0

.59~~~~~~~~~~~~~~~

Figure2. Alignment Char for Huma Studyin Geneal Physiology YaeUiest

-53~

AL .Hneso,Bod

BloIFo rs,0e

~ ~~~~~~9

ae,12,P

146

JOHN PARASCANDOLA

geometric construction, this figure can be transformed to an alignment chart, or nomogram, of the type invented by D'Ocagne.139While Henderson was in Europe in 1921-1922, D'Ocagne,who was quite pleased at the applicationof his method to a physiologicalproblem,showed him how to make alignment charts.140An alignment chart for human blood is shown in Figure 2. The values intercepted on the scales by any straight line are simultaneousvalues of all of the variables.The application of D'Ocagne'smethod to Cartesiannomogramsis only valid when the contour lines are approximatelystraight, but this is reasonably true for blood if one is dealing with values of the variableswithin the physiologicalrange. Henderson and his collaboratorsthen proceededto study the changes which take place in the blood in rest and work, health and disease, and from species to species. They used the nomogram to depict the changes which take place in total C02, total 02, and so on, during the respiratorycycle of blood.141Blood is not a closed system, of course, but it interacts with all the other systems of the body. He recognizedthat "a state of mutual dependence exists, not only between the different functions of the blood, but also between these functions and those of circulation and respiration, and the other physiological activities of the individual." His group therefore devised nomograms which expressed the relationships between factors such as the diffusimg capacity, coefficient of utilization of oxygen, head of oxygen pressure,bloodflow, and metabolicrate.142 Although Henderson admitted that the synthesis which he had achieved was imperfect and incomplete, he was confident that improvementsin experimental and mathematical methods would produce a more complete and more accurate synthesis in the future. The nomogram, he claimed, represents "the law of blood."'143 It has proved to be a useful tool for the biological scientist, particularlyin dealing with clinical problems of acidbase balance.'44It facilitates the visualization of relations be139. For an explanation of this transformation, see ibid., pp. 143-145. 140. Henderson, "Memories,"p. 257. 141. See Henderson, Blood, pp. 174-203, 236-329 for a summary of these researches. 142. Ibid., pp. 204-235; the quotation is from p. 204. 143. Ibid., pp. 147, 353-354, 357-358. 144. For examples of the use of nomograms, see H. W. Davenport, The ABC of Acid-Base Chemistry, 4th ed. (Chicago: University of Chicago Press, 1958), pp. 31-34; R. B. Singer and A. B. Hastings, "An Improved Method for the Estimation of Disturbances of the Acid-Base Balance of Human Blood," Medicine, 27 (1948), 223-242; and F. C. McLean, "Applications of the Law of Chemical Equilibrium (Law of Mass Action) to Biological Problems," Physiol. Rev., 18 (1938), 512-515.

96

Organismicand Holistic Conceptsof L. J. Henderson tween variables as well as saving the labor of computation. The nomogram has not come to serve as a model for treating complex systems of all sorts, however, as Henderson hoped it might. In 1929 he wrote in a letter to David Edsall, then Dean of the HarvardMedicalSchool: In all sciences which concern themselves with organism, (that is to say, in the physical and social sciences generally),

even the roughest approximationto a complete description of anything must involve the treatment of many variables. Also, such a treatment must be quantitative, because ordinary language is entirely inadequate for the treatment of such questions. Thus mathematics becomes the only possible language, and it is in practice, altogetherout of the question, to treat such considerations mathematically until the facts have been expressed quantitatively.Accordingly,if I am not mistaken, one of the most important aspects of our nomographic work is that it will serve as a model-of course a very imperfect, and, comparedwith some of the problemsinvolved, a very trivial model-which may help others in fields even very remotefrom that which we cultivate.'45 The study of blood as a physicochemical system may well have led Henderson to realize the utility of Bernard'sconcept of the milieu interieur. Certainly he interpreted this concept largely in terms of the regulation of the physicochemicalproperties of blood and other body fluids. It is probable that his attention was also focused on the theory of the internal environment through J. S. Haldane's extensive discussion of Bernard's doctrine in his Silliman Lectures, Organism and Environment as Illustrated by the Physiology of Breathing (1917).

Haldane saw organic regulation as the essence of life, a view which Henderson basically shared, and he clearly connected the concept of regulation with the theory of the internal environment.146Henderson was undoubtedly aware of this most important work, as he knew Haldane personally and was interested in his research. In fact, Haldane specifically mentioned these lectures in a letter to Henderson written near the end of 1917.147 145. Letter from L. J. Henderson to D. L. Edsall, July 27, 1929, Baker Library Archives, Harvard University.

146. J. S. Haldane, Organism and Environment as Illustrated by the

Physiology of Breathing, (New Haven: Yale University Press, 1917), pp. 68-80, 89-92. 147. Letter from J. S. Haldane to L. J. Henderson, December 23, 1917, Widener Library Archives, Harvard University.

97

JOHN PARASCANDOrA

It was in 1920, shortly after the work on blood had begun, that Henderson's first discussion of this theory in any detail appeared. In an article on acidosis, a subject which he had discussed several times previously without mentioning the milieu int6rieur,he noted the importanceof Bernard'sdoctrine for general physiology. We now know, he stated, that physicochemical conditions in the body fluids are regulated with an accuracy which could not have been forseen. He enumerated the main features of the doctrine of the intemal environment, which he considered to be a prophetic vision of the current ideas on regulatory mechanims.148 In the lectures on blood which he delivered at the University of London in 1925, he argued that the two most importantof Bemard's general views were his "opinionsconcering the existence of a peculiar and unfailing harmonious unty in vital phenomena"and "his hypothesis concerning the existence of a constant internal en149 Although it is possible, vironment in the higher animals." he suggested, to consider the latter theory as simply an important and interestingexample of the former view (that is, the phenomenon of organization), he felt that there was an advantage in emphasilzingeach concept separately.For the idea of a stable milieu int6rieur is more concrete than the abstract idea of organization.150 E. H. Olmsted has pointed out that Henderson helped to make Bernard'sviews available to Americansby promotingthe English translationof the Introductiona l'6tudede la m6decine exp6rimentalein 1927.X11In the 'Introduction"which he wrote to thi translation, Henderson again praised the theory of the internal environment. He asserted: 'A large part of the physiological research of the last two decades may fairly be regarded as a verification and illustration of this theory, which, as Claude Bernardperceived, serves to interpretmany of the most importantphysiologicaland pathologicalprocesses."152 In his monograph of 1928 he noted that the blood, as well as the nervous and hormonic systems, plays an important part

in the integration of the individual. The integrative activity of 148. Henderson, "Acidosis and Physicochemical Equilibrium," pp. 312-313. 149. Henderson, "Bloodand Circulation,"p. 176. 150. Ibid., pp. 178-179. 151. Olmsted, "Historical Phases in the Influence of Bernard's Scientific Generalizations,"p. 30. 152. L. J. Henderson, "Introduction," in Claude Bernard, An Introduc-

tion to the Study of Expermental Medcine, trans. by H. C. Greene (New York: Macmillan, 1927), p. viii.

98

Organismicand Holistic Conceptsof L. J. Henderson blood involves the theory of the milieu int6rieur,for it concerns the blood's function as the environment of the tissues.153He expressed the view, in a letter written in 1928, that blood serves as a means of communicationbetween differentparts of the body.154In Blood, he explained that this integrative action may be conceived as follows: The blood exists in a state of heterogeneous equilibrium with all the cells of the body. Suppose a change to occur in some part, say increase of activity in a group of muscles. Then the physicochemical equilibriumwithin these muscles will change, and this must be accompanied by changes in that portion of the blood which is in heterogeneous equilibrium with the varied muscle cells. This blood is carried back to the heart and mixes with all other blood. Changes in arterial blood result and these lead to changes not only in the respiratorycenter, but in all other parts of the body . . . every part of the body has at its disposal the resources of the whole body.'155 Although Hendersonmay perhaps be called, in the words of E. H. Olmsted,'56the "champion of Bernard in America," I must conclude that Bernard'stheoryreally had little or no effect on the direction of Henderson'swork. For he had already completed his studies on neutrality regulation, acidosis, and fitness long before he made any significant use of this doctrine. In addition, he had already begun his work on the interrelations between the variables of blood, and had discoveredhow to use the nomogram to describe these interactions, before any extensive discussion of the milieu int4rieur appearedin his writings. He apparently came to see this theory as a useful means of relating many of his own researches, as well as those of others, on the regulation of physicochemicalconditionswithin the body. It was to him an important generalization "which is perhaps destined to play an even greater role in the future than it has in the past."157 The nomogram of blood is in itself an excellent example of biological organization, for it illustrates the complexity of the interactions within the organism. The philosopher F. S. C. 153. Henderson, Blood, p. 366. 154. Letter from L. J. Henderson to J. A. McGillicuddy, January 19, 1928, files of L. J. Henderson, Jr. 155. Henderson, Blood, pp. 371-372. 156. Olmsted, "Historical Phases in the Influence of Bernard's Scientific Generalizations,"p. 29. 157. Henderson, Blood, p. 366.

99

JOHN PARASCANDOLA

Northrop, while a student at Harvard, was impressed by the nomographic work. He felt that Henderson had presented for the first time "a definite detailed picture of what organizationis, both analyzed into the relations and entities which it contains and yet revealed as the unified system which it is." 158 The nomogram, Northrop recognized, does not explain why the physiological processes are coordinatedin such a way that the organism tends to preserve itself in a state of dynamic equilibrium. He explained the integration of these processes on the basis of his macroscopic atomic theory, arguing that a huge hollow spherical atom must surround all of nature, forcing all atomic particlesinto an intimaterelationship.159 It will be recalled that Henderson had previously discussed the tendency of systems toward a state of dynamic equilibrium. He apparently preferred to accept this tendency as a law or basic fact of nature. The organism has a remarkableability to adapt to changes which threaten its equilibrium,and the adaptive character of organic phenomena cannot and should not be ignored.The law of adaptationin organisms,he felt, was as well established as the second law of thermodynamics.'80Henderson went on to argue: There is a disposition in certain quarters, among those who still permit themselves to deduce rules of scientific method from arbitrarilyassumed metaphysical principles, to object to the concept of adaptation as teleological and nonmechanistic. I hold, on the contrary, that the only objection that can fairly be offered is to the vagueness of the term. It must be remembered when we consider this question that the typical physical sciences are abstract,and for that reason they often exclude a priori the study of facts which lead to considerationsof the kind that adaptationinvolves. But even in pure mechanics the principle of least action and the concept of stability have taken an importantplace, while in engineering the terms efficiency, regulation, and adaptation are as familiar as in physiology. In these cases, concepts which some have regardedas teleological and non-mechanistichave tended to take the form of mathematicalfunctions which are implicit in the most mechanistic of all our scientific formula158. F. S. C. Northrop, "The Problem of Organization in Biology," unpubL diss., Harvard University, Cambridge, Mass., 1923, Preface and p. 9; the quotation is from p. 9. 159. F. S. C. Northrop, Science and First Principles (New York: Macmillan, 1931), pp. 195-204. 160. Henderson, Blood, pp. 16-17.

100

Organismicand Holistic Conceptsof L. J. Henderson tions, and this is also sometimestrue in the field of physiology. Thus the stability of the alkalinity of blood and protoplasm may be measured by the value of a mathematical function which is implicit in the general mathematical description of the equilibriumbetween acids and bases, and the regulation of alkalinity, that is to say, its relative constancy over a long period of time and under widely differentcircumstances,may be quantitatively described if we extend our studies from the physicochemical equilibrium of blood and protoplasm to the interaction of these with the activities of the lung and the kidney, and with the varying processes of metabolism. It is unreasonableto expect a precise definition of the term adaptationor the substitution of clearly defined terms for it, until greater progress has been made in mathematical physiology. Meanwhile there is one further remark which may be made. No characteristic of organisms is more certain than survival. Living things do in fact persist over long periods of time as physico-chemical systems which remain approximately in a stationary state. Now if we reject the considerations which are involved, however vaguely, in the use of the term adaptation and are excluded if we exclude it, if, in short, we limit ourselves to those considerationswhich belong to conventional abstract physics and chemistry, the survival of a single organism may be said to be almost infinitely improbable,and the continued existence of the flora and fauna of the earth an unaccountablemiracle.111 He elaborated somewhat on the subject of the organism's ability to adapt to changes and maintain its stability in a pair of lectures delivered in London in 1934. The resistance of organisms to change, he explained, depends partly upon the properties of water, carbon dioxide, and organic compounds. The stability of the temperature of both the organism and its environment, for example, depends upon the high specific heat and heat of vaporizationof water. Such properties, as he had explained in his earlier works, are not the result of natural selection. On the other hand, he noted, certain substances which contribute to physiological stability, such as hemoglobin, are clearly the result of natural selection. The heterogeneousnature of organisms also results in increased stability, for the phase rule indicates that as the number of phases in a system increases, the number of degrees of freedom in the system decreases (i.e. the stability increases). A heterogeneous system 161. Ibid., pp. 15-16.

101

JOEN PARASCANDOLA

generally affordsthe possibility of storage of reserves (as glycogen and fat in the solid state) and of means of escape (for example, carbon dioxide escapes in the gaseous state), and

these factors may be utilized in stabilizing the equilibrium.162 Finally, Hendersonfelt that the greaterthe number of interreladons between the variables of a system, the more stable the system will be. Such interconnectionsmay be assimilated to connections between the members of a mechanical structure, like a steel bridge, or to the structural arrangementthat is observed in bone. In general, it seems clear that the physico-chemical systems occurrig in organisms are characterizedby a very large number of quantitatively large physico-chemical connections between their parts, and that this ordinarilymakes for greaterstability.163 The nomogramof blood illustrates, of course, the large number of interrelationsbetween the components of one particular system in the organism. The blood itself is in turn interconnected with all of the other bodily systems, he pointed out. The integrative action of blood, which we have already discussed, made an importantcontributionto the stability of the organism in Henderson'sview.164 Living beings were not, In his opinion, the only systems which exhibited such stability and organization. We have already seen that he used such terms as order, adaptation, and teleology im referring to certain characteristicsof the inorganic universe.In an articlepublishedin 1918, he wrote: Moreover,all the characteristicsof the organizationof living things are not peculiar to such organisms. Thus it is generally admittedthat to speak of the organizationof society is more than a figure of speech, and the justification of this view is found in the similarity of regulatory processes and of

the conditions of stability in the two instances. It is true that each type of organization has its distinctive characteristics, but in large measure these depend upon the nature of the materialsorganized.165 At this time, however, Henderson was skeptical about the 162. L. J. Henderson, lecture I of three lectures delivered on the subject of equilibrium in the fileldof physiology, London, 1934, MS, Baker Library Archives, Harvard University, pp. 9-12. 163. Ibid., p. 13. 164. Ibid., p. 14. 165. Henderson, "Mechanism from the Standpoint of Physical Science," p. 575.

102

Organismicand Holistic Conceptsof L. J. Henderson possibility of studying social action in a scientific manner. In the 1920's, he began to take a greater interest in social problems, largely due to the influence of Dean Wallace Donham of the Harvard Business School. Donham has written the following accountof Henderson'sshift in interest: From about 1922 it was my good fortune to know Henderson well. As I came to appreciatethe encyclopedic and imaginative qualities of his mind and his combinationof learning with the highest degree of intellectual honesty, I fell into the habit of discussing with him the wider implications of the task facing a school of administration.Up to that time his intellectual interests had been focused on science-particularly on biochemistry and the history of science. In 1924-25 his interests in our problems became aroused, and he acquired an understandingof the dangers to organized society which arise from the specialized emphasis of the modem world on technological advance and the relative neglect by men of affairs of human problems which arise from such advance. In the fall of 1925 he came to see clearly the serious threat of these dangers to the future of science itself. His interest in such topics was stimulated further by Professor Elton Mayo after the latter joined the Faculty in 1926, to 168 study "HumanProblemsof Administration." The key factor which prompted Henderson eventually to become a serious student of sociology was the reading of Vilfredo Pareto's Trattato di Sociologia Generale of 1916. He was intro-

duced to this work in 1926 by his friend and colleague, William Morton Wheeler. Wheeler's study of insect societies had led him to an interest in human society as well. He was apparently impressed by Pareto'sbook and persuaded Henderson to examine it. The latter describedhis reaction to the work in a letter written to ProfessorJames HarveyRogersof Yale in 1933: It was the entomologistWheeler who first called my attention to Pareto's Sociology about seven years ago. I at first refused to look at the book on the grounds that all sociology is nonsense but he insisted and I found that so far as I was able to judge, he had been right and I wrong. The part of the book that I can judge with some qualification,namely that which has to do with scientific method, seems to me better than anythingelse that I know on the subject . . . As to the sociological parts of the book and the psycho166. Quoted from W. B. Cannon, "Lawrence Joseph Henderson, 1942," Biog. Mem. Nat. Acad. Sci., 23 (1943), 46.

1878-

103

JOHN PARASCANDOLA

logical parts, the only opinion that I have formed is that we have here a useful beginning and that Paketo's mistakes, though probablyvery numerous, and of course to a person like myself in nearly all cases unrecognizable,are of the kind we make in physiology, that they are quite as inevitable, taking account of our difficulties in working on the subject, as physiological mistakes and that people only have to continue long enough, skillfully enough, and in sufficient numbers and in the same way, in orderto correctthem.167 As Cynthia Russet has pointed out, Wheeler's instigation proved "catalytic,"for he "had chosen his man well."1"8 Pareto had received a scientific training and had started out as an engineer. He attempted to apply the methods of the physical sciences to sociology, and his style thus appealedto Henderson. Pareto treatedsociety as a system in equilibrium,and he stressed the concept of mutual dependence of variables, an idea which Hendersonhad himself made great use of in his work on blood. Pareto's work apparentlyconvinced him that it was possible to develop a scientific sociology, and he became a zealous missionary spreading the gospel of the Italian sociologist.

In his book on blood, Hendersoncomparedhis conception of an organism as a complex system in dynamic equilibrium to Pareto's view of a society, an analogy which the latter author also recognized. The following quotation from Pareto, conceming the equilibrium of the social system, was reproducedin Blood: . . . accidental changes of an element which arises, acts for a short time on a system, producingin it a slight deviation from the state of equilibrium,then disappears.For example, short wars for a rich country, epidemics, floods, earthquakes, and similar calamities, etc. Statisticians had already remarked that these events interrupt, for a brief period only, the course of economic and social life . . . The equilibrium

of a social system is similar to that of a living organism.169 In a little book which he published on Pareto in 1935, Henderson expressed the sociologist'sdefinitionof equilibriummore clearly: "If a small modification of the state of a system is imposed upon it, a reaction will take place and this will tend to 167. Letter from L. J. Henderson to J. H. Rogers, March 9, 1933, Baker LibraryArchives, Harvard University. 168. C. E. Russett, The Concept of Equilibrium in American Social Thought (New Haven: Yale University Press, 1966), p. 112. 169. Blood, p. 362.

104

Organismicand Holistic Conceptsof L. J. Henderson restore the original state, very slightly modified by the experience."170 Henderson compared this principle to Le Chatelier's theorem in physical chemistry. The equilibrium of the social system, he continued, is logically identical to physiological equilibrium, and he compared it to Bemard's concept of the constancy of the intemal environment and Cannon's theory of homeostatis.171In his lectures for "ConcreteSociology,"a course which he offered in the 1930's, he added that Hippocrates' conception of health as a state of equilibrium, with the body tending to counterbalance factors disturbing this equilibrium, expresses the same view. This emphasis on stability, or a tendency toward dynamic equilibrium,thus seemed to him to be a general characteristic of systems. Pareto's definition of equilibrium, he felt, applies to many phenomena and processes. "It is indeed a statement of one of the most general aspects of our experience, a recognition of one of the commonest aspects of things and events."172 The social system thus has regulatory processes, like the organism, which tend to stabilize it. To Henderson, the "sentiments" expressed by such words as duty, loyalty, and honor played a key role in the stabilizationof society. They are in fact necessary for the survival of society and the welfare of individuals. He shared Pareto'sbelief in the nonlogical nature of most human behavior, and in the human need for such sentiments.173His belief that the social system tends automatically to maintain its equilibriumsupportedhis conservativepolitical bias, for he hesitated to see changes made which might drastically upset this equilibrium. Henderson'sinfluence on American social thought has been summarizedby Cynthia Russett as follows: Henderson may have given greater impetus to diffusion of equilibriumconcepts among American social scientists than any other single individual.To a whole generationof Harvard students he passed on his conception of scientific method, of social science methodology and specifically of the place of equilibrium analysis in social science. . . . 170. L. J. Henderson,

Pareto's General Sociology: A Physiologist'8

In-

terpretation (Cambridge, Mass.: Harvard University Press, 1935), p. 46. 171. Ibid., pp. 46-47.

172. L. J. Henderson, "IntroductoryLectures in Concrete Sociology," MS, written and revised during the period 1937-1941, edited by Chester I. Bamard after Henderson's death, Baker Library Archives, Harvard University, p. 72. 173. Ibid., pp. 73-74, 181-193; Henderson, Pareto's Sociology, pp. 51-56; L. J. Henderson, "Science, Logic, and Human Intercourse," Harvard Bus. Rev., April 1934, pp. 317-327.

105

JOHN PARASCANDOrA

The roster of men who came under LawrenceJoseph Henderson's influence, whether as student, colleague, or friend, is long and distinguished.Among the Harvardfaculty during the 1930's Henderson's views measurably affected Wallace B. Donha.m, Elton Mayo, and Fritz Roethlisbergerof the Harvard School of Business Administration; the historian CraneBrinton;and the historian and essayist BernardDeVoto. The poet ConradAiken, the businessman ChesterI. Bamard, author of the classic organizationalstudy The Functions of the Executive, and the lawyer and legal historian Charles P. Curtis, Jr. also acknowledgedan intellectual debt to Henderson. George C. Homans and Talcott Parsons, both sociologists, and Eliot D. Chapple and ConradArensberg,anthropologIsts,absorbedsome basic Hendersoniantenets.174 At about the same time that he was first reading Pareto, he also began to think about the establishment of a laboratory which would promote a science of Human Biology by giving a generalizedscientific descriptionof individuals in their environment. As a result of his influence, the Fatigue Laboratorywas founded, in 1927, in the Harvard School of Business Administration. Its purpose was to study the physiological, psychological,

and sociological factors which affect the behavior of human agents in industry.'75Henderson moved into an office in the Business School and remainedin close contact with the activities of this Laboratory,although in the 1930's he devoted more and more of his time to his interest in Pareto. His emphasis on studying a total situation or a whole system is reflected in

the aims of the Fatigue Laboratory.This desire also shows itself in his urging to physicians to return to a Hippocraticview of the patient as a human being living in a social as well as a physical environment. He pleaded the case for a study of the "wholeman," for if we analyze a subject into too many aspects, we lose track of the whole.'76 One of his favorite quotations was: "Halfa sheep is mutton!" 174. Russett, Concepts of Equilibrium, pp. 117, 142-143. 175. On the founding, aims and history of the Fatigue Laboratory,see David B. Dill, "The Harvard Fatigue Laboratory, Its Development, Contributions, and Demise," Supplement I to Circulation Research, vols. XX and XXI, March 1967, pp. 1-161 to 1-170; anon., "The Harvard Fatigue Laboratory," Harvard Alumni Bull., Feb. 8, 1935, pp. 548-551. Dill indicates in his paper, p. I-163, that Henderson probably wrote most or

all of this anonymous article. 176. See L. J. Henderson, 'Physician and Patient as a Social System," New England J. Med., 212 (1935), 819-823; L. J. Henderson, "The Practice of Medicine as Applied Sociology,"Trans. Assoc. Am. Physicians, 51 (1936), 8-22.

106

Organismicand Holistic Conceptsof L. J. Henderson In the last decade of his life, Hendersondevoted his full time to philosophical and sociological questions. His last experimental paper was published in 1932. After 1936, he no longer taught (with the exception of the 1938-39 academic year) the biochemistry course which he had offered since 1905. Instead, he conducted a seminar on Pareto and a course entitled "Concrete Sociology: A Study of Cases." The latter course involved applying the principles of Pareto's system to a number of concrete sociological cases which were presented to the class by various colleagues or acquaintancesof Henderson. After reading Pareto, he became more and more skeptical of metaphysics. He came to regret the tone of certain parts of his earlier works, calling his "philosophical discussions of teleology, vitalism, and so forth, more or less irrelevant and immature." In his "Memories,"he remarked that in the period when he wrote his books on fitness and order, he had "a far less skeptical attitude towards philosophy and philosophers" than he later developed.As for his earlier attempts to explain the existence of fitness (in terms of a metaphysical teleological tendency), he came to regard what he had said on this subject as meaningless. It should be made clear that he never rejected the concept of fitness, and he always felt that it was the most interesting result of his own work.177W7hathe later regretted were the philosophical speculations which he had denrvedfrom it. He preferred,in later years, to regard the apparentexistence of fitness as a basic but inexplicable fact. In a letter written to J. B. S. Haldanein 1936, he stated: If I were writing now, I should write differentlybut without modifying the meaning of what I said. The meaning comes almost precisely to this: We know something about the general characteristicsof physico-chemicalsystems from the work of Gibbs and thousands of experimenters.We know a good deal about the system of the elements and the properties of the elements and of their compounds. Properties are heaped up on hydrogen, carbon and oxygen that make possible more experimentationof a physico-chemicalcharacter in any sort of evolutionary process because they make possible a greater range of variables in systems, a greater range in complexity, stability, etc. There is no lofty, speculative thoughtin this.178 He felt that he had clothed his earlier discussions of the sub177. Henderson, "Memories,"pp. 173, 185, 195, 198. 178. Letter from L. J. Henderson to J. B. S. Haldane, June 4, 1936, Baker LibraryArchives, Harvard University.

107

JOHN PARASCANDOLA

ject in inessential verbiage, that he had treatedit with an interest in words rather than things.179The use of phrases such as "perfectly changeless" or "absolutely changeless" in these books also disturbed him, for he became fully convinced that all knowledge is only approximate,not absolute.'80He wrote in a paperof 1932: I give warning in advance that my statements are to be regarded as approximatenot exact, as probablenot certain, and that if I fail to use these words in every paragraph,my motive is solely not to fatigue you. The only certainty about statements of experience (except possibly, but only possibly, logical and mathematical experience) is that they are not certain and not precise; some however are sufficientlyso for every-day use, but we are often slow to find out which. I believe that even this statement is an induction from experience and that it is only probable.181

By this time, he had concluded that all metaphysical statements, such as "the external world really exists," are nonlogical statements, that is, they are the expression of sentiments. They cannot be logically proved or disproved, and hence are meaningless for science.182 The question of the "truth" or reality

of a given theory is also meaningless. Conceptualschemes, he felt, are used because they are convenient, not because they are true or false in the sense of facts.'83 He came to agree with Ernst Mach that the greatest function of a generalization was mnemonic, or to economize thought.184In 1937, he wrote that more than ten years earlier he had finally accepted the statement of Henri Poincar6: "Maisil y a mieux; dans le m6me langage on dira tris bien: ces deux propositions,le monde ext6rieur existe, ou, il est plus commode de supposer qu'il existe, ont un seul et m8me sens."'185 While Henderson'sviews on the nature of science were undergoing some change even before he read Pareto's Trattato, 179. Henderson,

"Memories," p. 196; letter from L. J. Henderson

to

Darcy Thompson, January 22, 1938, Baker Library Archives, Harvard University.

180. L. J. Henderson, "Sociology 23 Excerpts," MS, 1941, Baker Library Archives, Harvard University, p. 86. 181. L. J. Henderson, "An Approximate Definitio of Fact," Univ. Calif. (Bereleeii) Publ. Phil., 14 (1932), 180. 182. Zbid., pp. 198-200.

183. Henderson, "Concrete Sociology," pp. 75-76; L. J. Henderson, "Science, Logic, and Human Intercourse," p. 318. 184. Henderson, "Memories,"p. 74. 185. Ibid., pp. 116-117.

108

Organismic and Holistic Concepts of L. J. Henderson this work certainly played an important role in shaping the philosophy of his later years. Pareto's emphasis on dealing with things rather than words, on the mutual dependence of variables, on the approximate nature of knowledge, is an important element in Henderson's later writings. Pareto also claimed that terms like "absolute" and "exist" had no real meaning for him. Hypotheses and theories were to him only instruments to enable us to picture the facts.186 "Theories, their principles, their implications, are altogether subordinate to facts and possess no other criterion of truth than their capacity for picturing them."'87 Sorokin has pointed out the sixnilarity of Pareto's methodology and view of science to the ideas of Mach and Poincare, two men whose opinions greatly appealed to Henderson in the latter part of his life.'88 There were three factors which Henderson came to feel were necessary for scientific work. The investigator must have intuitive familiarity with his subject, a systematic knowledge of the facts, and a good way of thinking about the things in question, i.e. a conceptual scheme. He noted that discussions of scientific method are more often concerned with the finished product, the published work of the scientist, rather than his habits and attitudes. For this reason, the importance of intuitive familiarity with the facts and theories of one's field of interest is often overlooked. "At each stage of his work before the final formulation and exposition, a skillful investigator is more often than not hardly aware of what he is doing, and much of his thinking is of the nature of revery and free association." 189 186. For a discussion of Pareto's view of science, see Vilfredo Pareto, The Mind and Society [Trattato di Sociologia generate], trans. Andrew Bongiorno and Arthur Livingston (New York: Harcourt Brace, 1935), I, 3-74. For his discussion of the mutual dependence of variables, see ibid., III, 1412-1419. 187. Ibid., p. 30. 188. Pitrim Sorokin, Contemporary Sociological Theories (New York: Harper and Brothers, 1928), pp. 41-42, 45. Mach and Poincar6, of course, also exerted an important influence on the Vienna school of positivism. See Phillip Frank, Modern Science and Its Philosophy (Cambridge, Mass.: Harvard University Press, 1949), pp. 6-12. Henderson was aware of the views of this group, but was not well versed enough in symbolic logic to really come to terms with these ideas. On February 18, 1937, he wrote to Rudolph Carnap concerning the latter's book, Logical Syntax of Language: "I think you know that I have never learned to use these symbols of modern logic, but it is clear that I must now take some steps in that direction" (Baker Library Archives, Harvard University). His paper on the definition of fact (footnote 181 above) shows, however, that he did have some interest in the problems of symbolic logic. 189. Henderson, "Concrete Sociology," pp. 63-66; the quotation is from p. 66.

109

JOHN PARASCANDOLA

Thinking appears to be impossible, he felt, without a conceptual scheme. The first conceptual scheme which we udlize, largely by instinct, is that of the common-senseworld. All other conceptual schemes are constructed with the help of this first theory.L90The invention or construction of hypotheses involves the imaginationto a large extent, he believed,and the psychology of the scientificinvestigatoris similarto that of the poet.191 Henderson, like the gestalt psychologists, stressed the combination or organization of sensations by the mind in perform-

ing a conceptual synthesis.192He felt that "experienceis an organic process, not a sum of parts." Subdivision

of experience

is arbitraryand can be misleading, like subdivision of physiological activity into functions.193Speaking of the scientist, he stated that "the activity of the man of science is all one process,

like the circulation of the blood, that in a sense we do violence in analyzing it into parts, and that all these parts are united into an organic whole, the activity of the investigator."194 Once again we see his constant emphasis on the need for a holistic or organicapproachin studyingmany phenomena. All conceptual schemes which take the form of systems, Henderson noted, have certain characteristics in common.'95He pointed out the similarities,for example, between Pareto'ssocial system and Gibbs'sphysicochemical system.'98These common characteristics depend in many instances upon "the logical necessity, or at least the high expediency, of setting up determinate conditions, because real conditions are found to be at least approximatelydetermined."'97In such conceptualschemes, one generally first postulates an abstract, ideal, isolated system. In order to determine the conditions of the system, certain variables must be chosen, the choice of which is determined by observation, experiment, logical and mathematical considerations,and convenience. Ideally, one would then try to obtain information about the mathematical functions by which the relations between these variables may be represented. In other words, one would like to describe the system by a set of 190. Ibid., p. 92. 191. Chester Bamard, "Introduction,"in Henderson, "Concrete Sociology," pp. 8, 31. In his "Memories," pp. 105-106, Henderson compared his

own way of working to that of his friend E. A. Robinson, the poet. 192. Henderson, "ConcreteSociology,"pp. 92-93. 193. Henderson, "Definitionof Fact," pp. 182-183. 194. Henderson, 'Concrete Sociology,"p. 78. 195. The following discussion of Henderson's views on this subject is based on his Pareto's Sociology, pp. 81-87. 91-92, 110-111, 114-115. 196. IbId.,p. 16. 197. IbId.,p. 82.

110

Organismicand Holistic Conceptsof L. J. Henderson equations involving the variables chosen, as Henderson did for blood. He recognized, however, that one often had to make do with qualitative data, and admitted that the prospect of a truly quantitativetreatment of the social system was remote. Another characteristicthat is generally indispensable in order that conditions be determinate, he felt, is the establishment of some definition or criterion of equilibrium.Pareto'sdefinition seemed to him to be the most comprehensive, as it included systems in a dynamic equilibriumor steady state, such as the organism, as well as systems in true thermodynamic equilibrium.'98In addition, another property of systems may be distinguished which depends more on psychologicalrather than logical characteristics of thought. "Manysystems, including the social system, contain 'objects'; these objects have 'properties'and 'relations' and they are 'moved' by 'forces.' Thus our kinesthetic needs find expression as they did in the discriminationof primary and secondary qualities and in Lord Kelvin's requirement of a model as an almost indispensable aid to the understanding of physical phenomena."'99 The analogy between various types of systems is due to these general psychological properties of thought and to the limitations that have been imposed on logical operations during the development of mathematics. When one applies such a generalized conceptual scheme to concrete systems, Henderson realized, he should proceed with caution. The concept of a social system as an ideal, isolated system is a useful generalization, but when dealing with a particular concrete situation, one must not forget that real social systems are not isolated from their environment. The investigator must then take into account other factors which depend upon this lack of isolation.200 Chester Barnard, the noted

businessman who became a good friend of Henderson'sin the 1930's, made the following commentary on the latter's view of the concept of system: In one aspect things discriminatedfrom their environment are systems when they are analyzableinto wholes consisting of parts. The primary process of discriminating systems is that of perception of unanalyzed wholes. It is evident that Dr. Henderson regarded the organizationof sensations as a Gestalt. The common-sense world of things thus discriminated was the basic and ineluctable world of science. He declined to go beyond this position philosophically.When the 198. Henderson, Lecture I of 1934 London lectures on equilibrium, pp. 6-9. 199. Henderson, Pareto's Sociology, p. 87. 200. Ibid., pp. 82-83. ill

JOHN PARASCANDOLA

Gestalt of anything has been analyzed by further perception into whole and parts, then one has a system. Thus a biological cell, blood plasma, an organ, a molecule, an atom, are mentioned by Dr. Henderson as systems. The analysis is usually of relations between parts and attendedby the discrimnination between a part and the whole. When the relationships are constant the substitution of new parts for old parts is not regarded as changing the system. For example, we regard a cell, tissue, the blood as continuous systems though the concrete componentschange. When the parts are maintainedbut the relationshipsare changing, we stdlldiscriminatea system; for example, the solar system. A change of relation between a system and other systems does not destroy the recognition of a system. Thus we may have changing parts, changing intemnalrelations, and changing external relations and still recognize a persistent system. An example is an eddy or whirlpool moving in a flowing stream. In such cases we apparently require the recognition of a stable principle organizing our apprehension of the concrete, either a pattem such as the Ptolemaic conceptionof an earth-centeredplanetarysystem or the principleof the gravitationalcontrolof orbitsof the planets in the heliocentric system. Thus either the ideas of stability, continuity, equilibriummay be regarded as essential to the concept of system, or the ideas of mutual relationships between components may be emphasized.Both ideas were used by Dr. Hendersonin defining'system.'201 Despite the changes that occurredin his view of science and philosophy, Henderson applied essentially the same methods and concepts to the various subjects that he studied. Throughout his career, he showed a concern for investigating the interactions between various components in a system or between different systems. He developed an interest in the questions of the organization,regulation, and equflibriumof systems fairly early in his researches, and these concepts became more explicit as he matured. In his attempt to make social science more scientific, however, he exaggerated the appropriateness and value of applyingconcepts derivedfrom the natural sciences to social studies. Paul Adams has commented: Henderson saw his shift from physical chemist to sociologist as a smooth and understandableprogression,not as a switch at all. Perhaps that was Henderson'sbasic error . . . He saw the knowledge frontier as existing in social science, 201. Barnard, "Introduction,"pp. 19-20.

112

Organismicand Holistic Conceptsof L. J. Henderson and he wished to utilize certain cognitive modes from the natural sciences in advancing sociology. To go from acidbase equilibriumto social equilibriumseemed for Henderson to be no wild jump between discrete universes of discourse.202

The research for this paper was begun while I was a graduate student in the History of Science Department at the University of Wisconsin. I wish to express my appreciation to Professor Aaron J. Ihde, who directed my Ph.D. dissertation, and to the National Science Foundationfor financial supportunder grants GS-972 and GS-1925. I also wish to thank the Josiah Macy, Jr. Foundation for enabling me to continue this work as a Macy PostdoctoralFellow in the History of Medicine and Biological Science at Harvard University. I acknowledge with special thanks the kindness of Lawrence Henderson, Jr., in permitting me to quote from his father's papers. Finally, I am grateful to Professor Everett Mendelsohnof the History of Science Department and Professor John Edsall of the Biology Department at Harvard for reading the original draft of this manuscript and offeringtheir valuable suggestionsfor improvement. 202. Paul Adams, "Lawrence J. Henderson: From Hasselbalch to Pareto," unpubl. lecture presented in the History and Philosophy of Medicine Series, University of Florida, May, 1969.

113

Notes on SourceMaterials: The L. J. HendersonPapersat Harvard JOHN PARASCANDOLA School of Pharmacy and Department of History of Science, University of Wisconsin, Madison, Wisconsin

Lawrence Joseph Henderson (1878-1942) was a man of such diverse interests that his personal papers should prove valuable to others besides historians of biology. Although he was primarily a biochemist and physiologist, his published works include treatises on subjects such as philosophy and sociology (see my article in this issue). He was an influential force at Harvard University during his career there, playing an instrumental role in the founding of the Department of Physical Chemistry in the Medical School, the Fatigue Laboratory, the Society of Fellows, and the history of science program. Jean Mayer commented in 1968 (J. Nutr. 94: 5): "To write of the history of science and its application to man in the United States during the first half of this century without mentioning L. J. Henderson would be to have missed one of the most important elements in the academic atmosphere in which they developed." The L. J. Henderson papers at Harvard University are located primarily in the archives of Widener Library and Baker Library, although the Countway Library also contains a few Henderson manuscript materials. These papers include correspondence, notebooks, unpublished lectures, rough drafts of publications, and similar items. Henderson's wide range of activities brought him into contact with scholars in many different fields. His correspondents included scientists (e.g., Joseph Barcroft, A. V. Hill, J. S. Haldane, Walter Cannon, and Raymond Pearl), philosophers (e.g., Josiah Royce, F. S. C. Northrop, and R. F. A. Hoernle), historians (e.g., George Sarton), sociologists (e.g., Pitrim Sorokin and James Harvey Rogers), and poets and writers (e.g., E. A. Robinson, Henry Mencken, and Bemnard de Voto). He was close to two presidents of Harvard University, A. Lawrence Lowell and

115

JOHN PARASCANDOLA

James B. Conant, and letters to and from both of these noted educatorsare containedin the collection. As an example of the information providedby these letters, we can consider the correspondenceconcerning two of Henderson's more philosophical works, The Fitness of the Environment, and The Order of Nature. In his letters to friends and critics, Henderson often clarified and elaborated upon certain points in these books. For example, he attempted to more clearly define his view of "teleology"in a letter written to Paul Lamsonin 1918 (BakerArchives): It is a little difficult for me to reply to your remarks concerning my two books and the idea of teleology. My own opinion is that what I have said is considerablyless philosophical than your interpretation of it. If you will look at a

living organism,or at a watch, you will find that it possesses, like many other things in the world, a pattern. There is a certain peculiarity, however, about the pattern of the watch which resembles the peculiarity of the pattem of the living organism, and differs from the peculiarity of the pattern of certain other things possessing other well-markedpattems, such as, for instance, the orbit of a planet, or a geometrical figure. This seems to me to be an objective characteristic of

the watch which we know to have been an excellent proof of the fact that the watch was designed. It seems to me also to be an objective characteristicof the organism, and, in the case of the organism, the current interpretationor explanation of it is that it is natural selection. What I maintain is that there is a pattem in the ultimate properties of the chemical elements and in the ultimate physico-chemicalproperties of all phenomena considered in relation to each other. I do not mean to say that this pattem is exactly of the same nature as the pattem of the watch or an organism. Still less do I mean to say or to imply anything about design or mind. The only minds that I know are the minds of the individual organisms that I encounter upon the earth. But I feel perfectly justified, in spite of a certain unavoidable vagueness and ambiguity,in using the word "teleology"for the patternin which I am interested. The important thing to my mind is, nevertheless, not any doubtful talking about the proper name to discuss such a thing, but the fact itself. That is to say, the objective fact that the propertiesof the elements bear a certain very curious relationshipto the processof evolution.

116

The L. J. Henderson Papers at Harvard While such letters enable us to better interpret Henderson's ideas, we also find correspondence which sheds light on the views of other important men. Letters from Josiah Royce, George Santayana, John Theodore Merz, and others, reacting to Henderson's works, provide insight into their thoughts about teleology and order in nature. For example, Santayana discussed, among other things, his views about consciousness in a letter written in 1917 (Widener Archives). He explained that he believed that consciousness exerts a physiological function by virtue of its physiological organ, the brain, but that consciousness or awareness in itself is a spiritual fact. It has logical and moral values, but no influence in the chain of material changes. Although some scientific realists deny the existence of consciousness, Santayana was convinced that it obviously exists. Henderson's correspondence with J. S. Haldane is interesting because it reflects the difference in attitude of these two important biologists with respect to the methodology and philosophy of physiological research. Haldane felt that his American colleague placed too much emphasis on physical chemistry as a practical basis for general physiology. He himself did not regard William Bayliss' Principles of General Physiology (1915), for example, as physiology at all. In a letter of 1929 (Baker Archives), he criticized Bayliss for "swallowing van't Hoff whole." Henderson replied that he recognized that physiology involved more than just physical chemistry, but that our knowledge of such complicated phenomena as the coordination of organic activities could advance only at a slow pace. The physicochemical conditions of bodily processes must be studied and understood, but at the same time one must not lose sight of the fact that these processes are organized into a whole. For those interested in the spread of Vilfredo Pareto's sociological ideas in America, the collection provides a rich source of information. Henderson was probably the leading disciple of Pareto in this country, and one can trace the development of his concept of the social system and his influence on men such as Chester Barnard, an important figure in American business history, in these letters and manuscripts. The correspondence indicates that Henderson was also acquainted with Walter Lippmann, who graduated from Harvard University. In fact, we find Lippmann writing to Henderson in 1938 (Baker Archives), after having read the latter's lectures for a course in sociology, that he is now prepared to admit that Pareto's conceptual scheme (as interpreted and improved by Henderson) is the best available.

117

JOHN PARASCANDOrA

A particularly unusual document is Henderson'sMemories, an unpublished autobiographicalmanuscript (265 pages) dictated in the period 1936-1939. Copies of this manuscript are deposited in both Baker Archives and Widener Archives. His purpose in writing this work, he claimed, was not autobiographical in the usual sense, but experimental. He felt that it would be interesting to try to recover from his memory such

interconnections of his thinling that he couldrecall.The aim was to find, by a process of introspection,those aspects of his intellectual experience which were most likely to coincide with the experiences of others. The value of such a project, in Henderson'sview, was as follows (p. 5): "Mypresent hypothesis is that if a sufficient number of persons whose experience has been with more ordinary affairs and largely scientific would make a serious attempt to recover their memories, something like scientific knowledge of the experience of ordinarymen of science might be recoveredfrom theirreports." Since Henderson emphasized his intellectual development, rather than the details of his life and career, the result is a manuscript which is most useful to the intellectual historian. Unfortunately,he never completed this fascinating experiment. After he recordedhis memories from childhood to about 1920, he lost interestin the projectand abandonedit. Other important manuscript materials in the collection include a typewritten statement by Henderson on the origin of the Society of Fellows, his correspondence with Sarton and others concerning the development of history of science as an academic discipline, his notes on courses taught by scientists such as T. W. Richards and Franz Hofmeister, and several of his unpublishedlectures. It is hoped that this brief description of the L. J. Hendersonpapers at Harvardwill serve to call attention to this valuablehistoricalresource.

118

Schroodinger's Problem:What Is Life? ROBERTOLBY Department of Philosophy University of Leeds, Leeds, England

It is probably true to say that the majority of biologists, biophysicists, molecular biologists, and possibly biochemists believe that the events which take place in an organism will eventually be described in terms of known chemical and physical laws. The majority of these scientists are then reductionists, and many would carry their reductionism beyond the stage of describing a living system as it is found to describing how it may have arisen. To them the organization apparent in living organisms can in principle be resolved into a historical process which heredity makes cumulative and natural selection makes adaptive, hierarchical, and thermodynamically less probable. We might describe them, then, as evolutionary reductionists as well as physiological reductionists. These reductionists would also expect that an organism should in principle be describable by analogy with a machine. They put their faith in mechanistic explanations. What organisms can do, machines in principle should be able to do. It is then difficult to be a reductionist without being a mechanist. But if we believe that the organization of machines and of organisms is irreducible, though physics and chemistry operate within them, then it is possible to be a mechanist without being a reductionist. As Schrodinger is chiefly concerned with the problem of reduction, I shall stick to this term wherever possible. When one learns the views of anti-reductionists like Wigner, Polanyi, Elsasser, and Koestler, one feels that there must surely be insurmountable obstacles in the way of the reductionist approach to provide a scientifically adequate description of life. Now few there are among us who really want all the mystery to be taken out of life; on the other hand, many of us would admit why we want to keep some mystery, i.e. Journal of the History of Biology, vol. 4, no. 1 (Spring 1971), pp. 119-148.

119

ROBERT OLBY

because we love mystery, and would therefore be at pains to distinguish between the philosophical, romantic, and scientific grounds for our attitude. All too often the reductionist attitude under attack is not one with which a self-respectingbiologist would care to be associatedtoday. And, what is more disturbing, some of the evidence cited as counter to molecular biological theory has long since found a place in that theory, as Dr. Francis Crick pointed out in his criticism of contemporary vitalists.1 Consequently, one feels cheated of the glimpse of new avenues of thought and research into the nature of life, and iritated by the dogmaticmanner in which such statements as "the whole is greater than the sum of its parts"are bandied about without any attempt being made to examine the extent of their validity. This is what happens when the antireductionists preach to the converted. To the historian of science, then, the period 1950 to 1970 will be of special interest as furishing a fresh instance of the backlash against the seeming overconfidence and intellectual despotism of the reductionist approach. The most prominent exponents of this revolt are physicists. The reasons for this, I suggest, are twofold. On the one hand they find the theory of evolution and the law of the survivalof the fittest utterlyforeign to their conception of physical theory and natural law. Thus Delbriickremarkedin 1949: To a physicist this evolution is a strange kind of theory . . . every biological phenomenon is essentially an historical one, one unique situation in the total complex of life . . . any

living cell carries with it the experiences of a billion years of experimentation by its ancestors. You cannot expect to explain so wise an old birdin a few simple words.2 Evolution is a statement about history, not a description of biological systems at any one moment in time such as can be verified by an experiment. On the other hand, many physicists alive today have lived through the intellectual excitement of a fundamental revision of physical theory, starting with the initially curious case of black-bodyradiation, which opened a crack in the tradition of continuity and led ultimately to the complementaryconception of electromagneticradiation as both wave-like and particulate. Niels Bohr, Gunther Stent, and Max 1. F. H. C. Crick, Of Molecules and Man (Seattle and London: University of Washington Press, 1966). 2. M. Delbruck, "A Physicist Looks at Biology" (1949), reprinted in Phage and the Origin, of Molecular Biology, ed. J. Cairns, G. S. Stent, and J. D. Watson (Cold Spring Harbor Laboratory, 1966), pp. 10 and 11.

120

Schrodinger'sProblem:What Is life? Delbriuckall hoped that biology would also reveal some such fundamental paradox and duality. The study of organisms would yield "otherlaws of physics."3 There is, at the same time, an obvious danger in scientists who work at one level predicting the future developments at another level. As Stephen Brush has reminded us: Whenever a scientist is tempted to criticize another scientist or a layman for being reluctant to give up his own ideas in order to swallow the latest scientific conclusions, he should remember the story of William Thomson and the age of the earth. Certainly if we tell our students about the battle between Galileo and the Catholic Church to show the need for freedom of research in science, we should also let them see what happens when a scientist becomes too confident of the universal applicabilityof his own theory.4 In the interests of clarity, we will not label these physicists as neovitalists; it would be better to call them antireductionists. They do not believe that life can be describedpurely in terms of chemistry and physics as we now know them. There will be other laws; hierarchicallaws peculiar to living systems. Known inter- and intra-molecular forces derivable from quantummechanical theory will not suffice. In the 1940's and 1950's mysterious long-range forces were discussed. Now, attention is focused on system and information theory. Thus Walter Elsasser's biotonic laws are those in which the information content of a system increases with time. We shall return to these ideas at the close of this paper. Our immediate concern is to ask the question: "What did Schrodinger find puzzling about the life of the cell, and what sort of scientific novelty did he expect would emerge?" ERWINSCHRODINGER There seems to have been a quality of mystery about Erwin Schrodinger,the unconventional, quizzical, Austrian physicist. "Whenhe went to a Solvay Conference,"says Dirac, 'he would walk from the station to the hotel where the delegates stayed, carrying all his luggage in a rucksack on his back and looking so like a tramp that it needed a great deal of argument at the reception desk before he could claim the room that had been 3. G. S. Stent, "Waiting for the Paradox," in Phage and the Origins of Molecular Biology, p. 8. 4. S. G. Brush, "The Role of History in the Teaching of Physics," The Physics Teacher, 7 (1969), 276.

121

ROBERT OLBY

reserved for him."5 E. T. S. Walton described him as quiet and unassuming: "he had no pose; his clothes were just what he thought to be most comfortable. He rode the humble bicycle. Of interest to him was his nose which he inherited from his grandfather [Joseph] [and] had been produced by a gene which had been held at 3000K for a century."6To Niels Bohr he proved especially tantalizing when with mock seriousness he opposed Bohr's statement of physical complementarityand with skillful sophistry evaded all the senrousDane's attempts to demolishhis objections.7 Several years after the publicationof his book What is Life?, Schrbdingerwas invited to address the biologists at Manchester University. As with Bohr, so with the Manchester biologists -he skillfully parried all attempts to probe more deeply into his ideas on the subject. What do we find in this slim volume based on a series of lectures given in Dublin in 1943, publishedin English in 1944, later translated into German, French, Russian, Spai'sh, and Japanese? If we look at his book from the biologist's point of view, and in an unhistorical manner, we have difficultyin discovering more than a physicist muddling his way along a circuitous path from quantum mechanics to the truisms of chemical and biological facts. Nearly two centuries of precisely collected empirical data tell us that chemical compounds exist and have stability in varying degrees. From the time of Dalton, discontinuity has been a feature of chemistry. Discontinuityin biology has had a more checkered career but by 1944 its place in biology was established, thanks to the work of the geneticists and taxonomists. The stability of such discontinuitiesin chemistry had been associated with the same features in biological systems in the nineteenth as well as in the twentieth century. We are not therefore surprised at the constancy in the hereditary transmission of Joseph Schrbdinger'snose shape to that of his grandson. We have all lived long enough to know that our bodies have a stable organization, the preservation of which demands a supply of free energy. None of us would care to attempt a

permanent fast in the cause of demonstratingthis self-evident 5. P. A. M. Dirac, "ProfessorErwin Schr8dinger,Foreign Member of the Royal Society," Nature, 189 (1961), 356. 6. From a letter described in E. C. Pollard, 'Erwin Schr5dinger 18871961," Progress in Theoretical Biology, 1 (1967,

id.

7. Professor L. Rosenfeld, personal communication. 8. Ibid.

122

Schrodinger'sProblem:What Is Life? fact, nor would we be attractedby the prospect of such a fast carried out at the absolute zero under which conditions, the physicists tell us, no free energy would be requiredto maintain our organization. For half a century we have been convinced that heredity depends on the chromosomes,and it has been common knowledge that these threads are able to replicate, though just how has been a source of speculation. Is it by a process akin to crystal growth or to enzyme action? We did not know, but we had faith in the view that physical chemistry would in due course account for it. We also believed that by natural selection a molecular structure had been arrived at whose fidelity of replication is suited to the organism'sdelicately balanced need for a certain degree of constancy, not too much and not too little. What then prompted Schrbdingerto write What is Life? In what has been said so far I have been guilty of adopting an unhistorical biologist's approach-and, for the 1940's, admittedly an enlightened one-and Schrbdingerwas not a biologist. True, his father used the time he could spare from the supervision of the family linen factory in Vienna to study botany and wrote papers on the phylogeny of plants.9 Schr6dinger's mother was the daughter of Alexander Bauer, chemistry professor at the Vienna Hochschule, and we may therefore believe that Schrodingerwas exposed to chemistry and botany from within the family circle. But such an exposure would not have given him the attitude I have described. His interest in biology stemmed from his desire for an all-embracing scientific knowledge of nature. The man who felt the urge to write on mind and matter, free will, and the nature of the soul would hardly be expected to leave out the nature of life.10 He later confessed that he had hoped to attend to general philosophical problems when he succeeded Fritz Hazenbhrl to the chair of theoreticalphysics at Czernowitz,but the annexation of Austria to Germany in 1938 put an end to this plan, and it was not until he was invited by de Valera to direct the Institute of Advanced Studies which the Irish Premier was setting up in Dublin that Schrodingerfound the peace and leisure to attend to such problems. There, in 1943, he gave a series of lectures to a general audience of about four hundred on the theme, 9. Erwin Schrodinger, "Biography," Nobel Lectures, Physics, 19221941 (Amsterdam: Elsevier, 1965), p. 317. 10. See Erwin Schrodinger, Science and Humanism: Physics in OUT Time (1951), Mind and Matter (1958), My View of the World (1964) (all published by Cambridge [Eng.] University Press).

123

ROBERT OLBY

"Howcan the events in space and time which take place within the spatial boundary of a living organism be accounted for by physics and chemistry?"'1And he advised them of his general conclusion at the outset: "The obvious inability of present-day physics and chemistry to account for such events is no reason at all for doubting that they can be accounted for by those sciences."12 In these lectures, Schrodinger deliberately shed the self-evident assumptions of biology and chemistry which I have described in order to ask as a physicist how his laws relate to what goes on in a living cell. In justice to him, let me quotehim on his approach: I propose to develop first what you might call "a naive physicist's ideas about organisms",that is, the ideas which might arise in the mnd of a physicist who, after having learnt his physics and, more especially, the statistical foundation of his science begins to think about organisms and about the way they behave and function and who comes to ask himself conscientously whether he, from what he has learnt, from the point of view of his comparatively simple and clear and humble science, can make any relevant contributionsto the question. It will turn out that he can. The next step must be to comparehis theoreticalanticipationswith the biologicalfacts. It will then turn out that-though on the whole his ideas seem quite sensible they need to be appreciablyamended. In this way we shall graduallyapproachthe correctview-or, to put it more modestly, the one that I proposeas the correctone. Even if I should be right in this, I do not know whether

my way of approach is really the best and simplest. But, in short, it was mine. The "naive physicist" was myself. And I could not find any better or clearer way towards the goal than my own crookedone.13 Schrodinger,then, admittedthe devious nature of his argument but evidently regardedit as necessary. The questions which he asked can be summarizedunder four heads: 1. How does the organism resist the tendency to the destruction of its organization? 2. How does its hereditarysubstanceremain unchanged? 11. Erwin Schridinger, What is Life? The Physical Aspects of the Living Cell (Cambridge Eng. University Press, 1944), p. 1. Hereafter referred to as Life. 12. Life, p. 2. 13. Life, p. 4.

124

Schrbdinger's Problem: VWhatIs Life? 3. How does this substance reproduce itself with such fidelity? 4. What is the nature of consciousness and free will? I shall not discuss question 4.14 In this way, I admit, the problem of reduction in biology is made far less daunting. Question 1 can be disposed of quickly, and we can then concentrate on questions 2 and 3. The first question can be rephrased as follows: The second law of thermodynamics states that order in the universe tends to disorder, organization and complexity are less probable, randomness and simplicity are more probable. Harold Blum, in the latest edition of his book, Time's Arrow and Evolution, defines the term order as follows: "If we picture a number of things that can be distributed in a variety of ways within a given space, we may say that the fewer the places these things can occupy the more orderly the system; the more places the things can occupy the more disorder."16 Thus the existence of carbon dioxide is less probable than that of carbon and oxygen, of a protein-lipid membrane less than a disordered mixture of the two, so long as the system is isolated from other systems with which it might enjoy an exchange of energy. If this, then, is a rule of nature-the entropy principle-how do organisms resist it? In 1852 William Thomson (Lord Kelvin) evaded the problem by simply confining the second law to inanimate agencies. He said: "It is inpossible by means of inanimate material agency to derive mechanical effect from any portion of matter by cooling it below the temperature of the coldest of surrounding objects."16 Helmholtz developed this restriction into a line of demarcation between the living and the dead.'7 The vital principle is like Maxwell's Demon, able to push processes in thermodynamically less probable directions. "This," remarked the Swiss physicist Charles E. Guye, in his book Physico-Chemical Evolution, "is evidently a very bold and gratuitous hypothesis, but one which it is interesting to recall in the presence of the insoluble mysteries of life."18 14. But see the excellent paper by U. T. Place, "Is Consciousness a Brain Process?" Brit. J. Psychol., 47 (1956), 44-50. 15. H. Blum, Time's Arrow and Evolution, 3rd ed. (Princeton, N.J.: Princeton University Press, 1968), p. 201. 16. W. Thomson, "On the Dynamical Theory of Heat . . . ," Proc.

Roy. Soc. Edinburgh, 3 (1852), 50. 17. H.

Helmholtz,

"Die

Thermodynamik

Chemischer

Sitzber. Akad. Wiss. Berlin, 2 (1882), 22-39. 18. C. E. Guye, Physico-Chemical Evolution, trans.

Vorgange,"

J. R. Clarke,

(London: Methuen, 1925), p. 103.

125

BOBERT OLBY

In a footnote to this remark Guye rightly pointed out that the organism "does not, by itself, constitute an isolated system." But for the best answer to the enigma we turn to F. G. Donnan's lucid article, "TheMysteryof Life"in 1928. The following passage refers to the physical impossibility of nonequilibrium, being generated spontaneouslyout of equilibrium-as if a tank of hot water were to cool itself down and the energy thus liberated to drive a fly wheel. Uncoordinatedenergy in statistical equilibrium,i.e. of even potential, does not spontaneously transform itself into coordinatedenergy. Now it would be a discoveryof tremendous importanceif plants or animals were found to be exceptions to this rule. But, so far as is known, the facts of biology and physiology seem to show that living beings, just like inanrimatethings, conform to the second law. They do not live and act in an environment which is in perfect physical and chemical equilibrium.It is the nonequilibrium,the free or available energy of the environment, which is the sole source of their life and activity. A steam engine moves and

does workbecause the coal and oxygen are not in equilibrium, just as an animal lives and acts because its food and oxygen are not in equilibrium. As Bayliss has so finely put it, equilibriumis death. The chief source of life and activity on this planet arises from the fact that the cool surface of the earth is constantly bathed in a flood of high-temperature light. If radiation in thermal equilibrium with the average temperatureof the earth's crust were the only radiant energy present, practically all life as we know it would cease, for then the chlorophyll of the green plants would cease to assimilate carbonic acid and convert it into sugar and starch. The photo-chemicalassimilation of the green plant is a fact of supreme importance in the economy of life. This transformation of carbonic acid and water into starch and oxygen represents an increase of free energy, since the starch and oxygen tend naturally to react together and give carbonic acid and water. Such an increase in free energy would be impossible if there existed no compensating running down or degradation of energy. But this running down or fall in potential is provided by the difference in temperature between the surface of the sun and the surface of the earth, a difference of some five or six thousand degrees. All living things live and act by utilising some form of nonequilibrium or free energy in their environment. The living cell acts as an energy transformer,running some of the free energy of 126

Schrodinger's Problem: VWhatIs Life? its environment down to a lower level of potential and simultaneously building some up to a higher level of potential."' There is, then, no problem with respect to the functioning of organisms and the second law of thermodynamics; the confusion has only arisen because writers have erroneously taken an organism for a closed instead of an open system. Sir Peter Medawar in his Herbert Spencer lecture in 196320 and Koestler in the symposium Beyond Reduction, 1969,21 gave the impression of having fallen into this trap. Nor do I see the evolution of organisms as incompatible with the operation of the second law. The history of phylogeny is one of increasing levels of potential energy per organism, but of course at the expense of the environment. The entropy "bill" has been paid in full. What many physicists have found so strange is the fact that, from one generation to the next, organisms do not have to "go back to square one"; the additional structuring of biological systems selected by differential survival is retained since the constancy of the genetic material applies to mutant as well as to wild type genes. Evolution is therefore cumulative and historical, which for Elsasser is a "biotonic law" (recently renamed "organismic"). But surely there is no law of evolution? There is no inevitability about its direction, which can be-thermodynamically speaking-neutral, positive, or negative. One might well make out a case for stating that the evolution of the elements and astronomical systems has been a more striking process than that of organisms. The fact is often overlooked that, biochemically speaking, the evolution of organisms shows a remarkable conservatism. As Paul Weiss has remarked recently: "There has been a reshuffling, re-sorting and recombination with emergent novelty and progressive improvement-yes, but it all had to start with the full complement of the minimum vital implements to begin with, because it is still the same assortment in the simplest amoeba and the highest metazoan. And this fact has not been publicised even though it has been stressed, for instance, by Florkin and Baldwin."22 In 1938 the 19. F. G. Donnan, "The Mystery of Life," Report of the British Association for the Advancement of Science, Glasgow, 96th Meeting (1928), p. 660. Reprinted in Annual Report of the Smithsonian Institution (1929), pp. 310-311. 20. Sir Peter Medawar, "Onwards from Spencer," Encounter 21 (1963), 40, 43. 21. A. Koestler and J. R. Smythies, eds., The Alpbach Symposium, 1968. Beyond Reductionism, in New Perspectives in the Life Sciences (London: Hutchinson, 1969), p. 53. 22. P. Weiss, in Koestler and Smythies (fn. 21 above), p. 46.

127

ROBERT OLBY

problem was thought so pressing that an international conference was held at the College de France in Paris to discuss it. Delegates were divided in their opinion as to whether the problem could ever be solved. A discussion of the same subject in 1946 at Harvard revealed the same diversity of opinion. Brillouin, IBM's Electronic Education Director, described the occasion in his paper, "Life,Thernodynamics and Cybernetics," and discussed the views of Schrddingerand Wiener. Brillouin's own conclusion was that "in addition to the old and classical concept of physical entropy, some bold new extensions and broad generalizations are needed before we can reliably apply similar notions to the fundamental problems of life and of intelligence."23 In view of this history of confusion, it seems a pity that Schrodingermade the problem seem greater than it really was, but there seems little doubt that this was intentional in order to dramatize the contrast between physical and biological systems. Thus, instead of talking about free energy upon which organisms feed, he used the term negative entropy.But, strictly speaking, this is a contradiction in terms. Entropy is positive above the absolute zero, zero at 0?K. Below that it is impossible to go. How then can there be negative entropy? Of course Schrodingerdoes not mean this, but he has been responsible for a term which has now been abbreviatedby Brillouin into the ugly word"negentropy." Summarizing our discussion of the first question, then, the answer is simple: organisms are open systems. Those who wish to read a contemporarystatement of the position will find the best account in that magnificently written book, The Structure of Physical Chemistry,by the late Sir CyrilHinshelwood.24 OFTHEGENETICMATERIAL PERMANENCE The question of the permanence of the genetic substance brings us to the central part of Schr6dinger'sbook. He had shown that by the device of a chemical code a huge quantity of infornation could be stored within a structure as small as a chromosome. This, to the biologist, was the most positive part of the book. From it, Schr6dinger drew one conclusion, which he confessed was his reason for writing the book: the

hereditarysubstance, "while not eluding the laws of physics as established up to date, is likely to involve 'otherlaws of physics' 23. L. Brillouin,

"Lfe,

Thermodynamics

and Cybernetics," American

Scientist, 37 (1949), 568. 24. Oxford: ClarendonPress, 1951. See chap. xxii.

128

Schrodinger's Problem: What Is Life? hitherto unknown, which, however, once they have been revealed, will form just as integral a part of this science as the former."25 It is difficult to be certain as to what sort of laws he had in mind. I shall simply attempt to characterize the problem confronting him and outline the way and extent of its subsequent solution. Schrodinger knew from the work of Delbruck, Zimmer, and Timofeeff-Ressovsky that the gene can be altered by X-rays and that the so-called "sensitive area" to these rays was reckoned to be equivalent to about 1000 atoms [molecular weight of the gene would then be approximately 14,000]. Now physical laws, he pointed out, are due to order based on disorder-to the statistical averages of numerous particles in random motion. For such laws, 1000 atoms are far too few. When he considered the Habsburg lip which had been reproduced faithfully in this famous Viennese family over a period of three hundred years, the problem seemed baffling, for during all that time, the gene concerned had been kept at 98o,0i-far above the absolute zero. . . .How are we to understand that it has remained unperturbed by the disordering tendency of the heat motion for centuries? A physicist at the end of the last century would have been at a loss to answer this question, if he was prepared to draw only on those laws of Nature which he could explain and which he really understood. Perhaps, indeed, after a short reflection on the statistical situation he would have answered (correctly, as we shall see): These material structures can only be molecules. Of the existence, and sometimes very high stability, of these associations of atoms, chemistry had already acquired a widespread knowledge at the time. But the knowledge was purely empirical. The nature of a molecule was not understood-the strong mutual bond of the atoms which keeps a molecule in shape was a complete conundrum to everybody. Actually, the answer proves to be correct. But it is of limited value as long as the enigmatic biological stability is traced back only to an equally enigmatic chemical stability. The evidence that two features, similar in appearance, are based on the same principle, is always precarious as long as the principle itself is unknown.20 Schrodinger went theory as applied to in 1926-27 justified aggregates of atoms 25. Life, pp. 68-69.

on to show how the quantum-mechanical the chemical bond by Heitler and London and accounted for the existence of stable called molecules to the satisfaction of the 26. Life, p. 47.

129

ROBERT OLBY

physicist. The atoms in a molecule are in an energy well, and to rearrange or extricate them requires the supply of energy. The mere act of heating them up may be all that is necessary, but for many molecules,bloodheat is inadequate. So far, Schrbdingerhas said no more than did the geneticist T. H. Morganin 1928: By stability we might mean only that the gene tends to vary about a definite mode, or we might mean that the gene is stable in the sense that an organic molecule is stable . . . There is little hope at present of settling the question. A few years ago I attempted to make a calculation as to the size of the gene in the hope that it might throw a little light on the problem, but at present we lack sufficiently exact measurements to make such a calculation more than a speculation. It seemed to show that the order of magnitude of the gene is near that of the larger-sized organic molecules. If any weight can be attached to the result it indicates, perhaps, that the gene is not too large for it to be considered as a chemical molecule, but further than this we are not justified in going. The gene might even then not be a molecule but only a collection of organic matter not held togetherin chemical combination.27

Unlike Bernal and W. T. Astbury, Schrodingerhad not noted the fact that viruses and chromosomes are composed of giant nucleoprotein molecules-surely a strange omission when he is trying to drive home the macromolecular nature of the genes.28 But mternal evidence suggests that Schrodinger deliberately avoided using chemical evidence. What he called a macromolecule was to Schrodinger, the physicist, ultimately indistinguishable from other aggregates in the solid state. For him, therefore, the problem remained of the atoms in a gene being held together in a fixed sequence despite thermal agitation. Instead of accepting the solution he had already given, Schrodingerwent on what now appears as a wild goose chase to find another solution. Thus he sets out the following table: molecule - solid - crystal gas - liquid - amorphous which schematizes the view that all stable arrangements of atoms are confined to the crystalline state, and what makes for 27. T. H. Morgan, The Theory of the Gene (New Haven, Conn.: Yale 28. Life, pp. 56, 69. University Press, 1928), pp. 320-321.

130

Schrodinger's Problem: What Is Life? stability in solids is the fact of crystallinity. All true solids are crystalline; hence all molecules with stable configurations of their atoms must be in the form of crystalline solids, for in liquids and gases there is no crystallinity and the individual molecules are at the mercy of thermal agitation. For genes to have a permanent arrangement, therefore, they must be solids, that is, crystals. To the question, "Why do we wish a molecule to be regarded as a solid-a crystal?" he said: The reason for this is that the atoms forming a molecule, whether there be few or many of them, are united by forces of exactly the same nature as the numerous atoms which build up a true solid, a crystal. The molecule presents the same solidity of structure as a crystal. Remember that it is precisely this solidity on which we draw to account for the permanence of the gene I The distinction that is really important in the structure of matter is whether atoms are bound together by those "solidifying" Heitler-London forces or whether they are not. In a solid and in a molecule they all are. In a gas of single atoms (as e.g. mercury vapour) they are not. In a gas composed of molecules, only the atoms within every molecule are linked in this way.29 Surely this is an oversimplification in terms of the knowledge of interatomic forces either in 1944 or 1970. It is true that between an ionic bond and a covalent bond there are intermediate structures but these do not prevent the two pure types of bond from being quite distinct. Molecules in which covalent bonds are operative do not lose their identity when their state changes from solid to liquid phase. And to ask whether the chromosome is in the solid state in the living cell is surely a meaningless question-it can hardly be described as crystalline! There may, of course be a formal physical sense in which all interatomic forces of affinity can be viewed as the samethey can all be described in terms of the Schr6dinger wave equation. This is clearly Schrodinger's approach, for he denies any fundamental distinction between macromolecules, the aggregate of atoms in a coin, and a batch of crystals in a copper wire.30 To make this point clearer let us consider what replication of the chromosome would be like (according to Schrodinger) in 29. Life, p. 60.

30. Life, pp. 58, 61. "The case of a molecule, a solid, a crystal are not really different. In the light of present knowledge they are virtually the same" (p. 58).

131

ROBERT OLBY

the light of more recent knowledge. A chromosome should be identical with a crystal formed by the crystallization of DNA subunits-the nucleotides. And DNA replication should be identical with the crystallization of nucleotide dimers from mixed nucleotide solutions. These dimers would be held in a fixed arrangementso long as they remained in the crystal state. But how could a chromosome of this sort function in metabolsm? How could it wind and unwind and go through the dance of mitosis, and all this in an aqueous environment?Such crystals in the environment of the cell would rapidly be dissolved, and then their arrangementwould be lost. Schrodinger,in What is Life?, oversinplified the picture and deliberatelyignored the unique character of the covalent bond, which unites neighboring nucleotides into a polymer chain. What irony that the man who was so anxious to emphasize the subtlety and sophistication of his reductionist approach missed the very spot where the subtlety comes in.31 For the covalent bond linking neighboring nucleotidesin DNA is, we believe, forged in the presence of an enzyme. Now Schrodingerwas no fool, and if he appearsto be talking nonsense it is surely the result of an unsubtle reading of a subtly conceived description. He had a very good reason for drawing an analogy between a polymer and a solid, which we will come to shortly. Suffice it to say here that he ignored the important point that the links in a polymer chain are forged in a chemical reaction in which free energy is extracted from the chromosome'senvironment. In this way the polymer may be said to have captured free energy and built it into the potential energy of its molecular structure;it is this that enables the hereditary substance to resist the disturbances of thermal noise. Another physicist, Walter Elsasser, like Schrbdingerturned away from the molecular explanation of the stability of the gene to the solid state. In his book, The Physical Foundation of Biology (1958), he quoted from an 11-year-oldtextbook of organic chemnistryon the reversible nature of reactions in the cell and the small energy changes associated with them. "If information was stored by virtue of chemical stability, a more efficient scheme for exposing it to the deleterious effects of molecular disorder,to what we have called noise, could hardly be invented."32Elsassergoes on to considerthe lobster: 31. Life, pp. 82, 86. 32. W. M. Elsasser, The Physical Foundation of Biology (London: Pergamon Press, 1958), p. 130.

132

Schrodinger's Problem: What Is Life? . . .an animal with an extremely hard external skeleton. If the lobster had studied electronic engineering the idea would at once occur to him that he could use the solidity of his shell to store information, for instance by depositing it in a hard membrane attached to the inside of the shell. But nothing of the kind is observed. Nobody will doubt that whatever information is significant for the lobster is functionally related to its 'soft' tissue, not much more firm than that of a jellyfish. This is a feature which we observe throughout the world of organisms. There is patently no correlation between the stability of information and the mechanical stability of the corresponding tissue, or if there is one it is distinctly negative. It is the delicate body of the embryo that can evolve into a richly structured system, not the sclerotic frame of the lobster. Now this is exactly the opposite of what all engineering experience and engineering principles would teach us . . . An optical engineer would have no quarrel with Nature about the construction of the eye as an optical system . . . The aviation engineer would not dream of quarreling with Nature about the principles of bird flight . . . But the electronic engineer will be radically at variance with Nature as to the way information should be preserved.33 The answer of the mechanist to this is surely that no computer has achieved so compact a storage of accessible and expressible information as the cell in its chromosome complement. A rough calculation gives the information content of the 1/2 u-long chromosome of the bacterium E. coli as equivalent to 1010 words. Man has 23 different and much larger chromosomes. What a vast library that represents I As far as the lobster is concerned I hardly need add that the storage of information on the inside of the exoskeleton would present serious problems when the animal moults its skeleton! GENE REPLICATION This brings us to Schrodinger's third question: How does the hereditary substance reproduce itself with such fidelity? You will recall that Schrodinger found a means of condensing a huge amount of information into a small structure like a chromosome by the device of a code. Unlike inorganic crystals, therefore, the hereditary substance would be aperiodic. Al33. Ibid., p. 129.

133

ROBERT OLBY

though to many crystallographersthe generation of a crystal with axes of symmetry from an aperiodic substance seemed unlikely, Schrodingersaw no problemhere, or at least he raised no difficulty on crystallographicgrounds, and rightly so. But how can such a structure "grow"or replicate? And how can it express the information encoded within its sequence of subunits? It was these two points that puzzled Schr6dinger.Here he expected "other laws of physics" to emerge. What did he expect to find? From the theme running through the book it is clear that the new physical laws would be what he called order-from-order laws, in contrast to known order-from-disorderlaws, and he termed the former "dynamical"and the latter "statistical,"following Max Planck, who in his paper, "Dynnsche und statistische Gesetzmassigkeiten"of 1914,34 identified dynamical laws with the microscopicworld of individual molecules and statistical laws with the macroscopic world of large numbers of molecules. In physics, as in biology, there existed a problem of reducing one set of laws to another, the macroscopic to the microscopic.Opiniondiffered as to whether this would or could ever be achieved. Whereas Maxwell ruled out the possibility of reducing statistical laws to the effects of Newtonian mechanics operating on individual molecules,35 Planck saw in such an attempt "one of the chief tasks of progressivescience" at which, for example, the meteorologistV. Bjerkneswas working in his attempt "to trace all meteorological statistics back to their simple elements, that is, to physical regularities."36 From this paper of 1914 it is clear that the Planck of those days hoped to bridge the gap between the behavior of the macroscopic and microscopic worlds by reducing statistical laws to dynamical laws. Planck, too, long treasured the classical conception of the role of probabilitytheory in physics as a provisionaldevice to be disposedof when the still deeply hidden causal factors are revealed.87Boltzmann had the same desire 34. M. Planck, "Dynamische und statistische Gesetzmassigkeit" (1914), pubL.in Physikalische Abhandlungen und Vortrage(Braunschweig: Vieweg, 1958), III, 77-90. This work is hereafter referred to as Vortratge. 35. W. D. Niven, ed., The Scientific Papers of James Clerk Maxwell (Cambridge (Eng.) University Press, 1890), II, 374; L. Campbell and W. Garnett, The Life of James Clerk Maxwell (London: Macmillan, 1882), p. 438. For a detailed treatment of this subject the reader is referred to P. M. Heimann, "Molecular Forces, Statistical Representation, and Maxwell's Demon," Studies in History and Philosophy of Science, 3 (1970), 189-213. 36. M. Planck, Vortrage,Im, 87. 37. M. Planck, "Eine neue Strahlungshypothese" (1911), in Vortrtige,

134

Schrbdinger'sProblem: What Is Life? and by his writings and followers he influenced Schrbdinger.88 Maxwell's legacy-the irreducibility of statistical mechanics -was for Planck, Boltzmann, and Schrodingera challenge and a sore in the body of physical theory. The contrastbetween the microscopicand macroscopicworlds was sharpened by the discovery of the discontinuity implied by the quantum of action (h). How was the continuity of energy assumed by classical physical theory to accommodate it? From 1900 to 1911 the quantum of action posed an increasing threat to the analogy between the continuity of energy at the macro-leveland the behaviorof energy at the micro-level. In 1911 Planck attempted first a classical interpretationof h,39 while at the Solvay Conference eight months later he argued that a physical interpretation of h could only be achieved by developing the quantum hypothesis, and that the laws of the

theory of quanta must apply to all particles united by the molecularbond.40 As if this were not enough, a further consequence of the quantum theory was pointed out by Werner Heisenberg when he enunciated the Uncertainty Principle which denies the determination of position and velocity of an electron, allowing only a probabilityestimate of the one parameter and a deterII, 259, and "tVeber die Begrindung des Gesetezes der Schwarzen Strahlung" (1912), ibid., 289; see also Max Jamner, The Conceptual Development of Quantum Mechanics (New York: McGraw-Hill, 1966), p. 49. 38. L. Boltzmann, Ueber die Unentbehrlichkeit der Atomistik in der Wien. Berichte, 105 (1896), 907-922; and Jammer Naturwissenschaft," (fn. 37 above), p. 256. See also E. Schridinger, "DynaTik elastische gekoppelter Punktsysteme," Ann. Physik, 44 (1914), 917. Jammer quotes from Schrodinger (1914) as follows: "Atomicity has the additional task by whose accomplishments alone its superiority over the phenomenological theories can be established. It has to discover and predict conditions under which the differential equations, based on the conception of continuity, would lead-because of the really atomistic structure of matter-to evidently false conclusions" (Jammer, p. 256). The influence of Boltzmann is also referred to by Y. Elkana, in translation of L. Boltzmann, "On the Development of the Methods of Theoretical Physics in Recent Times," Munich address, September 1899, publ. in The Philosophical Forum, 1 (1968), 94-120. 39. M. Planck, "Eine neue Strahlungshypothese" (1911), in Vortrage, II, 249-259. 40. M. Planck, "La Loi du rayonnement noir et l'hypothOse des quantit6s elmentaires d'action," in P. Langevin and de Broglie, eds., La Theorie du rayonnement et les quanta, Institut International de Physique Solvay (Paris: Gauthier-Villars, 1912), p. 114. This passage in the German version is in Planck's Vortrage, II, 285-286. See also A. Sommerfeld, '"Das Plancksche Wirkungsquantum und seine allgemeine Bedeutung fur die Molekularphysik," Physik. Z. 12 (1911), 1057-1068.

135

ROBERT OLBY

mination of the other.41Speaking of this in 1933, Schrodinger said: Will we have to be permanentlysatisfied with this? On principle, yes. On principle there is nothing new in the postulate that in the end exact science should aim at nothing more than the description of what can really be observed. The question is only whether from now on we shall have to refrain from tying descriptionto a clear hypothesis about the real nature of the world.42 This I believe to be the backgroundto his book What is Life? In the living cell, where order is based on order, he hoped physical laws of a deterministickind would be found. The organism is a macroscopic system which behaves in some of its aspects very like matter close to the absolute zero, where "molecular disorder is removed."43How does the hereditary substance achieve this? By being built like a clock "of solids, which are kept in shape by Heidter-Londonforces, strong enough to elude the disorderlytendency of heat motion at ordinary temperatures."44 This is where the purpose of Schr6dinger's crystalline-solidanalogy comes in. A gene and a clock are similar in that they are held together by Heitler-Londonforces. Strictly speaking, a clock behaves statistically, but for practical purposes we may say it behaves dynamically, for in the solid state, matter at room temperatureis equivalent to matter near the absolute zero where dynamical law reigns. So if Schrodinger was looking in any particulardirectionfor his new laws, it must have been toward the forces which hold the chemists' molecules and crystalstogether.45 But why the msytery about what appears a commonplace? I have already indicated one reason: Schrodinger'sfailure to entertain covalent bonds strong enough to resist thermal "noise" outside the solid state. This was perhaps understandablesince

he had grown up in a phase of physics which was powerless to deal with such problems as the physical basis of intra41. W. Heisenberg, "Ueber den anschaulichen Inhalt der quantentheoretischen Kinematik und Mechanik," Z. Physik, 43 (1927), 172-198. 42. Nobel Lectures.

Physics

1922-1941

(Amsterdam:

Elsevier,

1965),

p. 316. 43. Life, p. 70. 44. Life, p. 85. 45. This view has already been expressed in D. Fleming, "tmigr6 Physicists:

the Biological Revolution," Perspectives

in American History,

2 (1968), 176. This very interesting account should be read in conjunction with this paper.

136

Schr6dinger'sProblem: What Is Life? molecular forces of chemical affinity. Moreover,when he entered the University of Vienna in 1906, the chemists were devoting themselves almost entirely to small molecules. Later they were to deny the existence of macromolecules.For "special laws" they looked not to the solid state, as did Schrodinger,but to the colloidal state. We shall return to this point later. Another reason may well have been his natural tendency to liken gene replication to the growth of a crystal. No other inanimate system seemed relevant. But even here he noted a difference in that crystals grow by repeating the same structure in three directions, whereas a complicated organc molecule builds up an aggregate "without the dull device of repetition."46Note that he appears unaware of the other difference-the forging of covalent bonds in organic molecules and the absence of such formationsin crystal growth. I have outlined the "pitfalls"in Schrodinger'sanalysis and have attempted to show where he was unnecessarily perplexed. I have also pointed out that it may not be so much a question of pitfalls as the result of a deliberateuse of the crystal model as an analogy for the macromolecule. To what extent was Schrodinger'sposition representativeof that of the majority of biochemists, geneticists, and X-ray crystallographers of the 1940's? If we take the leaders of those sciences, then his position was surely unrepresentative.True, there had been a strong resistance on the part of biochemists and crystallographersto the concept of the macromolecule,but by the end of the 1930's the macromolecule was established. Crystallographersagreed that polymer chains could run through a whole series of unit cells. Biochemists were reluctantly agreeing with Hermann Staudinger that colloidal properties can result from macromolecular as well as from colloidal aggregate structures. And all this, despite the discovery that in the crystalline state the identity of single molecules is often lost. Yet, as we have seen, Schrbdingerwas confused on this issue in his desire to use the model of the solid aperiodic crystal. THE TEMPLATECONCEPT In another direction, too, Schrbdingerwas not abreast of current ideas circulating among structural chemists, biochemists and X-ray crystallographers:the nature of gene replication. In the prewar days of the late 1930's, much attention was paid to the process of mitosis, in which like chromosomes (homo46. Life, p. 61.

137

ROBERT OLBY

logues) are attractedto each other and are found to have replicated, each being transformed into a pair of chromatids. It was argued that perhaps the specific attractive forces which bring the homologues together in pairs also act in attracting the appropriatesubunits to the chromosome, where they are synthesized into a linear chain molecule identical with the parent chromosome on whose surface they have been formed. It was the American physical chemist H. J. Troland who in 1917 described the function of the gene as being both autocatalytic and heterocatalytic,the former leading to its replication, the latter to the fornation of nonchromosomalmaterial metabolically active in the cell.47 Though Troland's paper failed to arouse interest in the physical chemistry of genes and chromosomes, the process of chromosome pairing was widely discussed 14 years later as a result of the precocity theory of meiosis put forward by the British cytologist C. D. Darlington in 1931,48in his attempt to account in a mechanistic manner for the difference between prophase of meiosis and mitosis. From a detailed knowledge of chromosome coiling he was led to attributethe pairing of homologouschromosomesin meiosis to the precocious, or premature, onset of cell division. Normally

(in mitosis) the chromosomes would be divided into paired chromatids whose surface charges were mutually satisfied. In the absence of chromatidformation,he suggested, these charges were satisfied by chromosome-chromosomeattraction. Darlington went on to describe crossing over as a process of breakage and reunion of chromatids and to attribute it to the stresses and strains of molecular and higher-order spirals.49 "Muller,"

wrote Darlington, "at once saw the significance of my observations. We representedour problem to Astbury and Bernal first at the British Association meeting at Blackpoolin 1935. This led to the Klampenborgmeeting,"50organized by the Rockefeller Foundation to bring together physicists, chemists, and biologists. Muller again drew attention to the gene replication in his Moscow address, "Physics in the Attack on the Fundamental Problems of Genetics,"which closes with the following 47. L. T. Troland, "Biological Enigmas and the Theory of Enzyme Action," American Naturalist, 51 (1917), 329. 48. See C. D. Darlington, "Cytological Theory in Relation to Heredity," Nature, 127 (1931), 709-712, and, "Meiosis,"Biological Reviews, 6 (1931), 221-264. 49. See "The Internal Mechanics of the Chromosomes, III. Relational Coiling and Crossing Over in Fritillarla," Proc. Roy. Soc. [B], 118 (1935), 74-96. 50. Letter from C. D. Darlington, 21 January 1970.

138

Is Life? Schr6dinger'sProblem: WVhat words: "The geneticist himself is helpless to analyze these properties further. Here the physicist as well as the chemist must step in. Vho will volunteerto do so?" 51 In 1938 J. D. Bernal, in an unpublished lecture in Copenhagen, tried to do away with specific forces of attraction to account for chromosome pairing, postulating instead long-range nonspecific forces.52 The physicist Pascual Jordan rejected Bernal's suggestion and put in its place specific forces of attraction based on resonance: if the same sites on two identical or near-identicalmolecules differ in their energy states, the one being in an excited state, the other in the ground state, there would result a quantum-mechanicalstabilizing interaction between them, sufficient to account for chromosome pairing and possibly for chromosome synthesis. He doubted that normal valency forces would be adequate, as had been suggested for less complex synthetic processes, but he was left with the problem of how the rigidity of a molecule can be disturbed so as to raise parts of it to excited states. This he overcame by rejecting the wholly molecular model of the chromosome and introducing a "quasi-liquidstate of aggregation"of the atoms so that they are only loosely bound and can therefore undergo positional changes.53Two years later, his paper was seen by Linus Pauling, who promptly wrote a refutation of Jordan's theory which Delbruck and he published in Science. They believed the solution to questions of biological specificity would be found in the well-known covalent and hydrogen bonds, van de Waals, and electrostatic interactions.54Independent of them, Friedrich Freksa suggested electrostatic attractions between the basic histones and acidic phosphate groups of nucleoproteinsin place of Jordan'sresonance attraction.55

In the papers of Muller, Jordan, and Freksa, the idea of the chromosomemolecule acting as a template for the assembly of an identical molecule can be found, but Pauling and Delbriuck pointed out that if normal valency forces bring about template 51. H. J. Muller, 'Physics in the Attack on the Fundamental Problems of Genetics," Scientific Monthly, 44 (1936), 214. 52. J. D. Bernal, referred to by P. Jordan in "Zur Frage einer spezifischen Anziehung zwischen Genmolekulen," Physik. Z., 39 (1938), 711714. 53. Jordan, ibid., p. 714. 54. L. Pauling and M. Delbriick, 'The Nature of the Intermolecular Forces Operative in Biological Systems," Science, 92 (1940), 77-79. 55. Friedrich Freksa, "Bei der Chromosomenkonjugation wirksame Krafte und Bedeutung," Naturwiss., 24 (1940), 376-379.

139

ROBERT OLBY

function, what is importantis not structural identity but complementarity. These interactions are such as to give stability to a system of two molecules with complementary structures in juxtaposition, rather than of two molecules with necessarily identical structures; we accordinglyfeel that complementariness should be given primary consideration in the discussion of the specific attraction between molecules and the enzymatic synthesis of molecules . . . The case might occur in which the two complementary structures happened to be identical; however, in this case also the stability of the complex of two molecules would be due to their complementarinessrather than their identity. When speculating about possible mechanisms of autocatalysis, it would therefore seem to be most rational from the point of view of the structural chemist to analyze the conditions under which complementariness and identity might coincide.56 Eight years later, Pauling stated the conditions for the production of identical moleculesby complementaryreplication: If the structure that serves as a template (the gene or virus molecule) consists of, say, two parts, which are themselves complementary in structure, then each of these parts can serve as the mould for the production of a replica of the other part, and the complex of two complementary parts thus can serve as the mould for the productionof duplicates of itself.57

In the late 1930's gene replication had been discussed informally, and in 1939 W. T. Astbury gave nucleic acids a role in the processwhen he said: It is conceivable that in order to reproduce one chain exactly we have to pass through a succession of somewhat dissimilar chains before finally attaining the counterpartof that from which we started. And in this connexion we ought to bear in mind that only left-handed amino acids appear in the end-product: this suggests that a given protein is constructed either from an external molecular "template,"or it duplicates itself by somehow eliminating or overstepping intermediate enantiomorphous stages. In the latter case it 56. Pauling and Delbriick, Science, 92 (1940), 78. 57. Pauling, "Molecular Architecture and the Processes of Life," 21st Sir Jesse Boot Foundation

140

Lecture

(1948), p. 10.

Schrodinger's Problem: What Is Life? is just a possibility that one of the functions of a column of nucleotides is that of bridging the enantiomorphous stage. As we shall see shortly, the spacing of successive nucleotides in a column is almost exactly equal to the spacing of successive side-chains in a fully extended polypeptide.58 In this prewar scheme for gene replication, then, the nucleic acid played the role of a template "midwife" molecule supervising the replication of the proteinaceous genes. The first person to involve nucleic acids directly as the self-reproducing molecules as well as the templates for protein synthesis was Alexander Dounce in 1952. He suggested that the phosphate groups along the nucleic acid chain could arrange a sequence of either amino acids or nucleotides by forming covalent bonds with them. When the residues thus organized had been linked into a fresh polypeptide or polynucleotide chain, the links with the parent template molecule could be broken. Such reactions would require the presence of diphosphonucleotides and appropriate enzymes. His scheme was thus accessible to experimental investigation. Although he regarded base triplets as the probable mechanism for the "recognition" of amino acids, he thought an attempt at producing a stereo-chemical model premature. He said: An hypothesis for peptide chain and nucleic acid synthesis should of course take into account the geometry and spatial arrangements of the molecules in question, but it is doubtful whether enough is known of the details of nucleic acid structure to make attempts at calculations along these lines very profitable at present. Possibly some work with atomic models would be desirable. But in this connection one piece of evidence favorable to the proposed mechanism is worth mentioning, namely, the correspondence in a major spacing along the fiber axis that occurs between polynucleotides and polypeptides. This finding was thought to be of particular significance by Astbury.59 Dounce was unaware that in London, Pasadena, and Cambridge the structure of DNA was the subject of active research. As we all know, Watson and Crick supplied the mechanism for nucleotide-nucleotide fit in 1953, and after sixteen years of very intensive research it seems that the matching of adenine 58. W. T. Astbury, "Protein and Virus Studies in Relation to the Problem of the Gene," Proc. Int. Cong. Genet. (1939), 50. 59. A. L. Dounce, "Duplicating Mechanisms for Peptide Chain and Nucleic Acid Synthesis," Enzymologia, 15 (1952), 257.

141

ROBERT OLBY

with thymine and guanine with cytosine is reliable and genuine,

but not as reliable as Schrodingerimagined gene replication to be, for the discovery of enzyme repair mechanisms has revealed a frequency of mismatching greater than mutation rates calculated from observed mutant forms. There are, therefore, no solid grounds for asserting that DNA replication is more faithful than the mechanism of its synthesis would suggest. That it is more faithful than the specificity of H-bondformation between base pairs is held for certain by Professors Eigen and de Maeyer, who stated that "the error probabflityrangig below 10-8 to 10-10 carnot be ensured by the bond stability, since there is not much difference between the H-bondsin 'true'and 'false' complexes. It is more probable that the exact complementarity is expressed in the specific geometry of the pair, and that only this is recognized by the synthesizing enzyme."60

Eigen further noted the stabilizing effect of an existing base pair on the formation of a pair beside it, an effect he termed "cooperativity."8'Here, then, physics and biology are in harmony. One must not confuse base-pairingby hydrogenbond formation with the solution of the problemof replication.The nature of the unwinding process which permits replicationof the DNA duplex, and the enzyme mechanism whereby polymerizationof the sugar phosphatebackboneis achieved,are aspects of replication which await solution. Nor is it true that protein synthesis on a template of RNA can be achieved totally in vitro, whatever newspapers, including the Nature-Times Science Reports,

say to the contrary.62But this does not worry molecular biologists like Francis Crick, who regards as more important the understanding of all the components and their control mechanisms in one cell. His view is that: The problem of synthesizing it all and then putting it together on such a small scale-although a fascinating oneseems hardly worthwhile when one considers the immense amount of labor that would have to be involved in order to make everything synthetically. It would be more reasonable 60. M. Eigen, and L. de Maeyer, "Chemical Means of Information Storage and Readout in Biological Systems," Naturwiss. 53 (1966), 50-57. 61. M. Eigen, "Kinetics of Reaction Control in Enzymes," in Claesson, ed., 'Fast Reactions and Primary Processes in Chemical Kinetics," Proceedings of the 5th Nobel Symposium, 1967 (Stockholm: Alinquist & Wiksell;

New York: Interscience, 1967), p. 360. 62. Nature-Times News Service, "Basic Secret of Life Unlocked," The Times (London), Dec. 16, 1967. See also M. F. Perutz, "What Biologists Have Done," letter to The Times, Dec. 20, 1967.

142

Schrodinger'sProblem:What Is Life? to see if we could take it apart and then put the pieces together again, using componentsfrom broken cells, together perhaps with a few that had been made by chemical synthesis.63 The template concept is important in the history of biology and biochemistrybecause it has made conceivable the copying of an aperiodicstructure.Hitherto, polymer synthesis had been satisfactorily pictured only for homopolymers and for heteropolymers with simple repeating sequences such that the last residue of the growing chain determines what should follow it. Schrodingerrightly stressed the aperiodiccharacterof the chromosome chain but, as far as I can see, was at a loss to account for its replication. Yet we have seen that a way to the correct solution was emerging even before he wrote What is Life? That the attractive forces operating in template replication should turn out to be quite ordinary hydrogen bonds was a surprise to many and a vindication of the earlier predictions of Pauling which we have described. CONCLUSION Finally, we must ask how far has molecular biology taken us in the great program of reducing the biology of the cell to chemistry and physics? It has shown that the gene need not be a solid in order to resist thermal noise, that special forces are not required to achieve gene replication, and that the fidelity of this process is not as great as was formally envisaged. But the puzzle of the 1930's-how homologous chromosomes are attractedto one anotherover great distances-remains. Perhaps the long-range forces so much discussed in the 1940's64 lie at the root of this process, but there are already indications that the structure of the chromosome at the molecular level determines its structure at grosser levels,65 as was predicted by C. D. Darlington as early as 1935 and 1937.66 This brings me to the chief complaint urged against molecular biology, namely, that it is purely analytic. Thus, in the Alpbach Conference, "Beyond Reductionism," it is claimed that the 63. F. H. C. Crick, Of Molecules and Men, pp. 64-65. 64. See Gerald Oster's paper to the Conference on Long-range Forces at Brooklyn Polytechnic Institute: "Two-phase Formation in Solutions of Tobacco Mosaic Virus and the Problem of Long-range Forces," J. General Physiol. 33 (1950), 445-473. 65. C. Person, and T. Suzuki, "Chromosome Structure-A Model Based on DNA Replication," Can. J. Genet. Cytol., 10 (1968), 627-647. 66. C. D. Darlington, Recent Advances in Cytology, 2nd ed. (London: Churchill, 1937), pp. 438.

143

ROBERT OLBY

atomistic and hierarchicalexplanations are quite distinct;67and further, that "the mere reversal of our prior analytic dissection of the Universe by putting the pieces together again, whether in reality or just in our minds, can yield no complete explana-

tion of the behaviour of even the most elementary living system."68 We have sought to show that what Weiss calls discontinuity between orders of magnitude is present in chemistry and physics as well as in biology. Weiss himself admits that, although the reversal of analysis fails to give us a complete explanation of living systems, this procedure of analysis and synthesis must be credited with "the tremendous success of science over the last two millennia."69 Who is expecting a complete explanation anyway? Moreover,it is abundantlyclear from the history of science that the failure of reduction to give completeexplanations does not prevent the parts extractedfrom a system from being put together again by the experimentalist so as to generatethat system anew. Admittedly, many assumptions have to be made before the characteristics of a molecule of a compound like benzene can be predicted from the interaction of its constituent atoms in accordance with quantum mechanics. These assumptions are usually shruggedoff as mere problems associatedwith the solution of equations, but it is difficult to see how the claim to absolute predictive power of quantum theory in chemistry can at the same time be maintained, and it is clear that unless we know many of the characteristicsof benzene from our experience of the whole molecule beforehand,we can never be in the position to make the right assumptionsby which alone we can deduce from quantum mechanics the features of the benzene molecule. Clearly, physics and chemistry as well as biology are in no position to deduce any hierarchical levels from those beneath them without foreknowledgeof some of the characteristics of the higher levels to be deduced. This does not prevent the reductionist approach from being successful in extending man's command over nature by virtue of his increasing understanding of biological processes in terns of chemistry and physics. When it is said that certain biological laws are irreducible,it is not generally meant that their deduction from physics and chemistry is impossible but that they are so incompatible with those subjects as to make description of them in terms of physical 67. P. A. Weiss, "The Living System: Determinism Stratified," in Koestler and Smythies, The Alpbach Symposium (fn. 21 above), p. 8. 68. Ibid., p. 7. 69. Ibid.

144

Schriodinger'sProblem: What Is Life? and chemical processes impossible. Thus Elsasser has recently cited what he terms variostability as an example of an irreducible phenomenon-the diversity of individuals of an interbreeding population and the stability of each individual.70 Although there is a difference of many orders of magnitude between individual differences in animals and those in proteins it is difficult to see why variostability cannot be equally applied to a series of proteins differing in one or a few amino acid residues or even to a series of aliphatic hydrocarbons. The view of most molecular biologists, it seems, is that hierarchical laws can or will be described in terms of physical and chemical laws. Hence, they see the study of living systems in terms of known physicochemical laws as a more promising approach than the pursuit of nonphysical laws. There is at the same time no advantage to be gained from denyig the validity of either approach. Where a structure is too complex for the reductionist approach, a hierarchical description will be appropriate. The history of biology is replete with examples of such "holons," which later give way to a lower level of analysis, yet retain a certain value (gene, cistron, triplet). As long ago as 1917, Donnan emphasized the molecular basis of individuality, drawing an analogy between the individuality of a molecule such as benzene and that of the living cell. He urged the value of studying the history of individual complex molecules. Detailed knowledge of even a moment of the life of such molecules would be welcomed by biologists at once, he said.7' Most molecular biologists maintain that there is a continuum between the chemistry of inanimate matter and of life. Hierarchical laws result from the laws governing the association of atoms into molecules and of molecules into mycells, gels, membranes, and organelles. The reducibility of hierarchical levels is then a problem throughout science, and it is very doubtful that Michael Polanyi's distinction between the reducible and the irreducible aspects of organisms and machines72 is valid. According to him, the inanimate and nonmachine world is entirely reducible, but machines and organisms have a dual control; physicochemical laws rule in them, but their structure 70. W. M. Elsasser, "The Role of Individuality in Biological Theory," in C. H. Waddington, ed., "Towards a Theoretical Biology, 3. Drafts," IUBS Symposium (Edinburgh University Press, 1970), pp. 161-162. 71. F. G. Donnan, "La Science physicochimique. Decrit-elle d'une facon adequate les phenomenes biologiques?" Scientia, 24 (1918), 286. Donnan's papers are cited in a footnote to What is Life? 72. M. Polanyi, "Life's Irreducible Structure," Science, 160 (1968), 1308-1312.

145

ROBERT OLBY

imposes "boundaryconditions"on the ways in which these laws may be expressed. As long as we believe in the validity of pushing back the process of evolution by natural selection to

the evolution of life itself, we cannot accept Polanyi's distinction. The structure of organisms has then to be reduced to a historical process, the course of which has been determined by physicochemical laws. To physiological reduction we hope to add evolutionaryreduction. Reduction to what? To the laws of physics and chemistry,whateverthey may be. That they may be revised we must allow; hence our reductionism is always temperedwith a fundamentalrelativism. Our problem is neither a philosophical one, nor a romantic one, but a question of strategy. Where is it most likely that a purely hierarchical description will be fruitful and where a reductionist analysis? Strategy and fashions are closely associated in science. What is really under fire is the current fashion of the reductioniststrategy as exemplifiedin the popular image of molecular biology. Schrbdingerundoubtedlyhad much to do with setting this fashion. It was his provocativeand deliberately naive way of writing about biology which gave his book such an impact among physicists. A similar book by a physical chemist would surely have had less impact. What is Life? influenced many physicists, among them FrancisCrick,who wrote: . . . in spite of all the things you say about Schrodinger's

book, one has to recognise that it had a very important influence on younger scientists who were considering entering biology. It certainly did on me, and Jim Watson and Seymour Benzer have also told me that they were influencedby it. The point is that it made the subject seem exciting and gave the impression to novices that this way of thinking about things would be an interesting line to follow. I cannot recall any occasion when Jim Watson and I discussed the limitations

of Schrodinger'sbook. I think the main reason for this is that we were strongly influenced by Linus Pauling, who had essentially the correct set of ideas. We therefore never wasted any time discussing whether we should think in the way Schrodingerdid or the way Pauling did. It seemed quite obvious to us that we shouldfollow Pauling.78 Yet it is ironical that the real goal Schrodingerhad in mind -the discovery of order-from-orderlaws in the special hierarchical conditions of the cell-was of no interest to these physicists. How fortunate for molecular biology was this lack 73. Letter from Dr. Crick, 15 January 1970.

146

Schrodinger's Problem: VWhatIs Life? of interest in the latter part of Schrodinger's book, What is Life?! No paradoxes, no order-from-order laws, have emerged. Instead organisms are held to achieve order from disorder by a historical process ruled by differential survival. What vision of these new laws did Schrodinger have? It was, I suggest, a vision of quantum mechanics operating under conditions imposed by a special structure as yet undisclosed. We may like to regard this structure as the system with its all-important cellular components in which DNA replicates. Let us close with a passage from What is Life? which expresses the sort of problems in explanation of the working of living matter which Schrodinger anticipated must lie ahead: . we must be prepared to find it working in a manner that cannot be reduced to the ordinary laws of physics. And that not on the ground that there is any "new force" or what not, directing the behaviour of the single atoms within a living organism, but because the construction is different from anything we have yet tested in the physical laboratory. To put it crudely, an engineer, familiar with heat engines only, will, after inspecting the construction of a dynamo, be prepared to find it working along principles which he does not yet understand. He finds the copper familiar to him in kettles used here in the form of long, long wires wound in coils; the iron familiar to him in levers and bars and steam cylinders is here filling the interior of those coils of copper wire. He will be convinced that it is the same copper and the same iron, subject to the same laws of Nature, and he is right in that. The difference in construction is enough to prepare him for an entirely different way of functioning. He will not suspect that the dynamo is driven by a ghost because it is set spinning by the turn of a switch, without fumace and steam.74 Here Schrodinger ruled out vital forces for organisms as he ruled out a ghost for the dynamo, but it is evident that he expected laws would emerge from the behavior of the cell's contents of a more radical nature than anything molecular biology has uncovered-laws as novel as the electromagnetic forces operating in a dynamo. Acknowledgements This paper is the revised text of a lecture given to the British Society for the History of Science on January 2, 1970. The 74. Life, p. 77.

147

ROBERT OLBY

author is grateful to many colleagues at the Botany School, Oxford, and the Philosophy Department, Leeds, for advice, instruction and discussion, in particular to Dr. Keith Fuller (Oxford) for instruction on the entropy principle and to Peter Heimann (now at Cambridge) for instruction on problems in nineteenth-and twentieth-centuryphysics. The analysis of Schrodinger's book was undertaken at the suggestion of Dr. Francis Crick, who drew the author'sattention to the seemingly clumsy and circuitous character of Schr6dinger'spresentation of the subject. It is a pleasure to thank him and the British Society for the History of Science for the opportunity to present the paper.

148

An UnacknowledgedFoundingof Molecular Biology:H. J. Muller'sContributionsto GeneTheory,1910-1936 ELOF AXEL CARLSON

Department of Biological Sciences State University of New York, Stony Brook

The origins of molecular biology are numerous and diverse. Three major routes, however, stand out in having attracted its contemporarypractitioners.These may be characterizedas the genetic, the structural,and the philosophic origins of molecular biology.' In 1953 all these approaches were united in a single world-viewthrough the double helix model of DNA.2 Genetics, like the later founding of molecular biology, also cannot be associated with a single origin. The nineteenth-centuryhistory of genetics consisted of the independent activities of plant breeders, cytologists, and evolutionists, and it was not until 1915 that the theory of the gene (then called the factorial 1. In the past few years several historical treatments of molecular biology have appeared. Chief among these are Stent's "That Was the Molecular Biology that Was," Science 160 (1968), 390; Stent's introductory essay, "Waiting for the Paradox," in Phage and the Origins of Molecular Biology, ed. J. Cairns, G. S. Stent, and J. D. Watson (Cold Spring Harbor Laboratory for Quantitative Biology, 1966); J. D. Watson, The Double Helix (New York: Atheneum, 1968); and Donald Fleming's essay, "Amigr6 Physicists and the Biological Revolution," in The Intellectual Migration, ed. Donald Fleming and Bernard Bailyn (Cambridge, Harvard University Press, 1969). The major theme of these views is the influence of Delbruck and Schrodinger in the founding of the genetic or informational school of molecular biology. It is my intention in this essay to call attention to the role Muller had in shaping their views. I have also added a philosophic basis to the origins of molecular biology; Stent emphasizes particularly the roles of the structural and informational schools. The biochemical contributions I have considered under the genetic or structural roles, but Kornberg, Chargaff, and others would probably list it as an independent role; see Kornberg, Nature, 214 (1967), 538, and E. Chargaff, Essays on Nucleic Acid (New York: Elsevier, 1963). 2. J. D. Watson and F. H. C. Crick, Nature, 171 (1953), 737-738 and 964. Journal of the History of Biology, vol. 4, no. 1 (Spring 1971), pp. 149-170.

149

ELOF AXEL CARLSON

hypothesis) brought the unification of these tributaries of genetics into a single world-view.3 The parallel between the origins of genetics and the origins of molecular biology is also similar in the often contradictory or unrelated motivations which are associated with their chief contributors.A detailed study of these motivations is no longer directly possible in genetics because most of the pioneers are dead. For molecular biology, however, almost all its major contributorsare alive, and we have been rewardedwith highly personal accounts in Watson's Double Helix, in Stent's review "ThatWas the MolecularBiology That Was," and in Delbrick's Festschrift, Phage and the Origins of Molecular Biology.4No doubt future essays and memoirs by its major participantswill retain this self-analytical, rather than narrative, interpretation of history. No such highly personal accounts exist, however, for Mendel, Bateson, Morgan, deVries, Castle, Demerec, or Bridges.Very limited personal histories are available for Sturtevant and Beadle.5Muller had attempted an abbreviatedDouble Helix of his own, which was obscurely published in a Soviet popularjournal.8Were it not for the reprintsof it which Muller had sent to a select mailing list, his conflict with Morganmight not have become intractable.There are, furthermore,published and unpublished self-analytical notes on Muller'scontributions to classical genetics which he wrote over a fifty-year span. These reveal considerable knowledge about the activities of Morgan's fly laboratory and at least suggest, from Muller's perspective,how the theory of the gene emerged between 1910 and 1915. Although the theory of the gene is a major tributary to 3. Somewhat differing views of this early history of the Drosophila group are found in A. H. Sturtevant, A History of Genetics (New York: Harper & Row, 1965); L. C. Dunn, A Short History of Genetics (New York: McGraw Hill, 1965); E. A. Carlson, The Gene: A Critical History (Philadelphia: Saunders, 1966); and J. Schultz' review of the latter, Science, 157 (1966), 296. 4. These influences are discussed more critically by P. B. Medawar in New York Review of Books, March 28, 1968, and in G. Stent, Quart. Rev. Biol., 43 (1968), 179. 5. Sturtevant, American Scientist, 53 (1905), 303-307; G. and M. Beadle, The Language of Life (New York: Doubleday, 1966). 6. H. J. Muller, "Lenin's Doctrines in Relation to Genetics," in To the Memory of V. 1. Lenin, Press of Academy of Science, Moscow-Leningrad, 1934. This document should be read in historical context as one of the first criticisms

of Lysenkoism.

Muller's anti-Morgan feelings

were also

exacerbated by Morgan's decision to share his Nobel Prize money with Sturtevant and Bridges. For biographical background see E. A. Carlson, Can. J. Genet. Cytol., 9 (1967), 436.

150

H. J. Muller's Contributions to Gene Theory, 1910-1936 molecular biology, it is not acknowledged as such-for example, in the two accounts of Stent. Nor do most molecular biologists who were trained after World War II have an awareness of how much is owed to the influence of gene theory, especially through Muller's contributions. In this respect there is no parallel between the origins of molecular biology and those of genetics. An analogous situation might have occurred if Bateson, deVries, Correns, Tschermak, and Wilson had ignored Mendel's rediscovered papers as past history or of little consequence to the new approaches and theories of the turn of the century. Among the accepted genetic contributions to molecular biology are 1) the "green paper" of Timofeef-Ressovsky, Zimmer, and Delbriuck ("On the Nature of Gene Mutation and Gene Structure") appearing in 1935; 2) the "one gene: one enzyme" theory of Beadle and Tatum worked out in the early 1940's; 3) the transformation of bacteria by DNA, first shown by Avery, Macleod, and McCarty in 1944; 4) the founding of the bacteriophage group, primarily by Delbriick, Luria, Doermann, and Hershey from 1937 to 1948; and 5) the remarkable insight of Erwin Schrbdinger, who interpreted genetic phenomena with a molecular phrasing in his influential book, What Is Life?7 The structural legacy of molecular biology has British origins, especially the X-ray diffraction analysis developed by the Braggs and applied to proteins and viruses by Astbury and Bernal in 1939; also influential was the laborious X-ray diffraction analysis of substituted hemoglobins and myoglobins by Perutz and Kendrew (a 20-year project beginning in the 1940's). Linus Pauling's alpha-helix in 1951 provided the model-building approach later used by Watson and Crick. Independent of the x-ray diffraction and model-building approaches was the new insight into the cytological fine structure of cellular organelles, especially through electron microscopy, from the late 1930's to the early 1950's, with Palade and Sjostrand among the most prominent in this burgeoning field. The third component of this structural legacy comes from the cell fractionation approaches using ultracentrifugation, chromatography, radioautography, and electrophoresis. Largely a product of the biochemical and biophysical schools of the 1930's and 1940's, its participants worked independently of the genetical and structural schools until the "one gene: one enzyme" theory made the union of these diverse approaches seem feasible.8 7. Cambridge(Eng.) University Press, 1944. 8. See Stent's review in fn. 1 above for details of these structural achievements.

151

ELOF AXEL CARLSON

One of the philosophic

approaches to molecular biology

comes from Bohr's speech, "OnLight and Life," which he presented in 1932.9 Bohr believed that a new physics was required for interpretinglife. Although Bohr did not consider his views mystical, the materialistic school of biologists resisted such approximationsto indeterminacy, holism, or "structuralvitalism" because of their earlier experience with the limited approaches of Driesch, Semon, and Bergson for developmental and evolutionary biology, and of Pearson, Castle, East, and Goldschmidtfor genetics. Nevertheless, Bohr'sessay influenced Delbruck,who abandonedphysics for the new world of biology. Only a few of the key figures in molecular biology are known to have had their initial interest aroused by Bohr'sphilosophic view-Delbriick and Schrodingerhave acknowledgedthis initial belief. Stent, although not as prominent in the developmentof molecular biology, was also brought in by this route. There are others, excluded from the orthodoxmolecular school, who still accept Bohr's belief; some of these are Elsasser, Szent-Gyorgi, and Wigner among the physicists and biophysicists.10For awhile the geneticist J. B. S. Haldane accepted this view despite his political materialism.11Parallel to the physicist's anticipation of new laws for biological phenomena were the new forns of discredited or questionable biological views ranging from vitalism to an undefined purposiveness,or holism. Among these schools of thought, those of E. S. Russell, Edmund Sinnott, and Barry Commoner are the best known and most influential.12

Another philosophic contributionto molecular biology comes from Schr6dinger'sunacknowledgedphysical paraphaseof Muller's contributions to gene theory. Two major insights were proposedby Schrodinger:one of these, the "aperiodiccrystal," represented the structure of the chromosome fiber, and the other, the "codescript,"representedthe specificityof the genetic 9. N. Bohr, Nature, 131 (1933), 421. 10. See Crick's criticism of the neo-vitalists in Of Molecules and Men (Seattle: University of Washington Press, 1966); also, W. M. Elsasser, The Physical Foundation of Biology (London: Pergamon Press, 1958), and E. P. Wigner "The Probability of the Existence of a Self-Reproducing Unit," in Symmetries and Reflections (Bloomington: Indiana University Press, 1967), pp. 200-210. 11. J. B. S. Haldane, New Paths in Genetics (New York: Harper Co., 1942). 12. E. S. Russell, The Directiveness of Organic Activities (Cambridge (Eng.) University Press, 1946); E. Sinnott, Cell and Psyche, (Chapel Hill: University of North Carolina Press, 1950); B. Commoner, Science and Survival (New York: Viking Press, 1966).

152

H. J. Muller's Contributions to Gene Theory, 1910-1936 information. It was these aspects, representing material-its only a few paragraphs of What Is Life?, which became so influential. The quantum model of mutation developed by Delbrick and the endorsement of Bohr's anticipation of new physical laws for biology, which constitute the bulk of Schrbdinger's book, were less significant in the intellectual development of Crick, Watson, Luria, and Benzer.13 Out of Schrodinger's book, therefore, is the first intimation of a coding problem and the first popularization of the structural nature of the gene sought earlier in the technical publications of Astbury and Bernal. It is not widely recognized, however, that both the concept of genetic specificity and the special structure of the gene were developed much earlier by Muller. Moreover, two implied concepts in What Is Life? -the uniqueness of the gene among all other biochemical molecules and the virtual monopoly of gene activities as the basis of life-were developed by Muller. THE PRE-MULLERIANVIEWS OF THE GENE Prior to the rediscovery of Mendel's publications on the laws of heredity, there was a strong belief in the atomicity of 13. Stent, in a footnote to his Science article, reveals how few molecular biologists were influenced by the Bohr-Schrodinger belief in new laws of physics. However, Schrodinger's What Is Life? was influential in interpreting genetic biology in physicists' terms. It attracted a new wave of physicists to biology, including F. H. C. Crick and Seymour Benzer. Schrodinger himself did not initiate any laboratory approach to molecular biology, nor did he fashion a school of his own. He gave to Delbriick the laurels for the genetic viewpoint, which, as I shall attempt to demonstrate in this essay, belong in part to Muller. Fleming, in his provocative essay (fn. 1 above), assigns an emigr6 role to the founding of molecular biology. I do not argee with this view because the structural view (crystallography, Bragg, x-ray diffraction, and model-building) is both Continental-Bernal, Watson. The biochemical comAmerican-Pauling, Wilkins, Crick-and ponent (forced on Delbruck and now accepted as part of molecular biology) stems initially from Beadle and Tatum (American) and Ephrussi (Continental and American); and for genetic coding, its molecular solution is both Continental (Brenner, Crick) and American (Nirenberg), as well as 6migr6 (Ochoa, after Nirenberg; and Gamow, whose erroneous coding theories set Crick and Brenner on the right track). Some of these complex international relations and nationalistic viewpoints are summarized in The Gene (see fn. 3 above), chaps. 18, 19, 22, 24, 25. Fleming also assigns an important founding role to Leo Szilard. Szilard, unlike Delbruck or Luria, had no school of his own. His phage work and his analysis of mutation rates by construction of chemostats was not of unusual significance. If he did play a role, it was through another effect, which Fleming points out: the influence of a major physicist switching to biology and thereby setting a pattern of emulation for younger physicists. I would not, however, have included Szilard as a founder of the molecular biology school.

153

ELOF AXEL CARLSON

heredity. These views were particularlystimulated by Darwin's theory of pangenesis and by Spencer's theory of physiological

units. Toward the end of the nineteenth century Weismann proposed similar hereditaryunits for differentiationin development; and deVries removed the Lamarckianweakness of Darwin's pangenesis by offering a theory of "intracellularpangenesis," whose units, like Weismann's,resided in the chromosomes, but which could undergo qualitative and quantitativechange.14 All these speculative theories of heredity were displacedby the excitement of the Mendelian rediscovery.Bateson, dominating this period of rediscovery, popularized the Mendelian factors, or "elemente,"as Mendel called them, and he introduced the terms allelomorph (abridged later by Shull to allele) and unitcharacter for the hereditaryunits. Confusion between the variations in character and a correspondinginstability of the inferred unit determnng the character led to polemical debates over these units. Gradually,there was a wearing away of the term unit-characterto an unhyphenatedunit character,then to a unit factor, and finally to an undefined gene, truncated by Johannsenfrom deVries'concept of pangenes.15 During this debate over the symbolism and the terminology for the gene, several views emerged. Bateson abandoned the double-factortheory of Mendel (i.e., the dominant and the recessive genes are both present in a heterozygote) for the "presence and absence" theory which he, Hurst, and Correns had developed.18DeVries abandonedhis own rediscoveryrole, after being disappointed by Mendel's priority and by the crowded number of rediscoverers and near rediscoverers, including Correns,Tschermak,Bateson, Spillman, and Wichura. Instead, deVries popularized his mutation theory as a replacement of Darwin's theory of natural selection. At the time, the significance of an alternativeto Darwinismwas more rewardingthan 14. A more detailed account of the evolution of these conceptual units is covered in chap. 3 of The Gene (fn. 3 above). 15. G. H. Shull was the first American geneticist to introduce Johannsen's term (American Naturalist, 43 [1909], 410). Morgan and his students used it sporadically in their publications from 1910 to 1915, but kept the term factor for their text (The Mechanism of Mendelian Heredity [see fn. 32 below]). By 1917 the term gene was in widespread use and the term factor had lost its vogue. A curious parallel in the late 1950's saw the term gene replaced by Benzer's term cistron. Both terms are used almost as synonyms by biologists, but Watson's preference for the "gene" (The Molecular Biology of the Gene [New York: Benjamin & Co., 1965]) may have reversed the molecular sentiment for the cistron. 16. R. Swinburne, "The Presence and Absence Theory," Annals of Science, 15 (1965), 67-82.

154

H. J. Muller's Contributions to Gene Theory, 1910-1936 the rediscovery of Mendelian laws.17 Castle, among others (including Morgan until 1910), had claimed that the stability of these factors was a fiction, and he proposed instead that the genes were altered every generation either through selection, through heterozygous contanation, or through an inherent multiphasic instability similar to Galton's earlier "polygon of instability" for heredity.18 This association of fluctuations in character phenotype with corresponding changes in the Mendelian factors may be called the unit character fallacy. Also during this early period, a purely idealistic concept of the genes as mutational symbols was promoted by East.19 Another view, that of a holistic physiological theory of gene action, was developed by Goldschmidt.20 Additionally, there were numerous naive preformationist views which were entertained by Bateson's school through the rigid identification of each character with a specific gene.21 Despite the mutually contradictory philosophies of these schools of thought, all were united by the belief that the factors, or their abstract representatives, obeyed Mendelian transmission ratios. Quite outside these contending factions was the prominent mathematical school founded by Weldon and Pearson on Galton's laws of ancestral inheritance, which attempted -to continue Darwin's tradition of gradual speciation through the natural selection of imperceptible variations.22 Also outside the Mendelian camp were the numerous biologists who accepted Lamarckian views on the inheritance of acquired characteristics.23 In the first decade of the twentieth century, all three of these widely divergent approaches to heredity had equal merit, at best, to the larger group of biologists who were not engaged in studies of heredity. Actually, the sympathies of the times would probably have favored the neoLamarckian theories as the best available interpretations of heredity and variation. 17. DeVries' Mutation Theory proposed the origin of species by single mutations, presumably by massive alterations of the pangenes. He based his theory on the unusual progeny of evening primroses, Oenothera lamarchiana. Ironically, Muller was one of the earliest critics of this theory and had used his genetic analysis in Drosophila to work out an alternative to deVries' model (see H. J. Muller, Genetics, 3 [1918], 422). 18. For a summary and evaluation of Castle's polemical attacks on the stability of the gene see The Gene (fn. 3 above), chaps. 4 and 5. 19. E. M. East, American Naturalist, 46 (1912), 633. 20. R. Goldschmidt, Science 43 (1916), and 119 (1954), 703. 21. C. Hurst, "Mendelian Characters in Plants and Animals," Report of the Third International Conference of Genetics (1906), 114-128. 22. W. F. R. Weldon, Biometrika, 1 (1901), 228. 23. Including W. K. Brooks, the graduate school teacher of Wilson, Morgan, and Bateson. See his Foundations of Zoology (New York: MacMillan, 1899).

155

ELOF AXEL CARLSON

From this analysis it is clear that the Mendelian revolution was by no means an overnight event. It was badly fragmented and lacked the unifying world-viewof Darwinism. That unity of view was partially accomplished,first, by Morgan'stwo major contributionsof sex-linked inheritance and crossing over; second, by Sturtevant's contribution of chromosome mapping; third, by Bridge'scontributionof nondisjunction as a proof of the chromosome theory; and, fourth, by Muller's clarification of the relations between gene and character. These four components of the "factorial hypothesis" established the physical basis of heredity and diminished the stature of the contending schools of Pearson, Bateson, deVries, Goldschmidt,Castle, and the neo-Larmarckians.24 THEDEVELOPMENT OFMULLER'S GENETHEORY What is often called classical genetics was almost entirely worked out in the period 1910-1915. In these few years the rediscoveryof Mendelismand its associationwith the process of meiosis was greatlyextended. Sex linkage, crossing over, genetic mapping, genetic and cytologicaldemonstrationsof the chromosome theory, nondisjunction, aberrations of the chromosome, and the relation of characters to genes were all resolved as soon as each new exceptional breedingphenomenon or mutant fly arose. The parts played by the Drosophila group varied.25 Morgan played the major role in 1910 and 1911; he was an equal contributor in 1912, and by 1913 almost all the new phenomena were picked up and analyzed by his students. Sturtevant was the sage. He read all the availablegenetic literature; 24. In addition to the references in fn. 3 above, the rise of classical genetics is treated by H. J. Muller in "The Development of the Gene Theory," in Genetics in the 20th Century (New York: MacMillan, 1951), pp. 77-99. 25. This is an area of controversy. My views are based on conversations

with H. J. Muller and Edgar Altenburg as well as readings of Muller's unpublished

letters

and manuscripts.

I have

also interviewed

A. H.

Sturtevant and other students associated somewhat later with Morgan's laboratory (A. Weinstein, J. Schultz) for different views of the Drosophila group (see Sturtevant, fn. 3 above) and Schultz (fn. 3 above). Especially valuable among Muller's published papers are "A Decade of Drosophila"(in Russian), Prog. Exp. Biol. (USSR) 1 (1922), 292, translated by J. Wilkinson and deposited in the Muller archives, Lilly Library Bloomington, Indiana, and "Lenin's Doctrines in Relation to Genetics" (fn. 6 above), which is available at the TLillieLibrary, Marine Biological Laboratory,Woods Hole, Massachusetts. Also useful is A. H. Sturtevant's unpublished paper 'Personal Recollections of Thomas Hunt Morgan," read before the National Academy of Sciences, April 25, 1966.

156

H. J. Muller's Contributions to Gene Theory, 1910-1936 at 19 he conceived of mapping the chromosomes; his major role was the coordination of the group discussions. Bridges was a gifted experimentalist with unusually perceptive abilities to spot abnormalities. Almost all the exceptional phenomena were first observed by him. Bridges, however, lacked the brilliance of Sturtevant and the genius of Muller. Both Sturtevant and Bridges joined Morgan's laboratory in 1910, the year Muller had graduated from Columbia. Although Muller's commitment to genetics began in 1908, before Morgan's Drosophila work had become productive, Muller participated as a discussant in the new work from 1910 on. Muller at this time was earning his living at Cornell Medical School and the Physiology Department of Columbia Medical School because he had no financial support from Morgan. He worked without enthusiasm on physiological problems (creatine metabolism at Cornell and, for his M.A. at Columbia, nerve pulse transmission). In his discussant role in the "fly lab," however, he offered the theoretical basis for the new phenomena and, especially with Sturtevant, designed the crosses for Bridges to carry out. In 1912 Muller obtained a teaching assistantship in the Zoology Department but he was given a separate room by Morgan (I believe Morgan did this to prevent his other students from feeling dominated by Muller's forceful personality). Muller was the zealot of the group. He attempted to fit all genetic phenomena into the chromosome theory. He proposed the law of linear linkage and designed the tests to show that Sturtevant's maps were not convenient diagrams but actually demonstrated the linear arrangement of the genes. He worked out, with Sturtevant, the relation between map length and chromosome length and the correspondence between linkage groups and chromosome number. He took over the stubbom non-Mendelian cases which Morgan could not resolve and devised the means to "dissect" the chromosomes through crossing over, locating the chief gene and modifier genes which he had anticipated; he predicted the presence of a Y-chromosome in nondisjunctional females and, with Sturtevant, designed the crosses to demonstrate the genetics of nondisjunction. The first chromosomal aberration detected was the deletion; when Bridges found a round eyed reversion of the dominant bar eye, he noted that it had replaced bar eyes with a recessive lethal and he was about to discard the stock as no longer of interest. Muller, however, rescued it and predicted that a deletion of genetic material had occurred. He designed the crosses to test this hypothesis, and Bridges

157

ELOF AXEL CARLSON

found that an extensive segment had indeed been removed from the X chromosome.26 The group did work, if not harmoniously, at least cooperatively, and Bridges was generous in supplying the laboratory with his new mutants and his peculiar breeding results. There was resentment by Muller and Altenburg that Morgan had slighted them by excluding them from his laboratory work space. There was also little interest by Morgan or Sturtevant in the radical political views which Muller and Altenburg espoused. In temperament Sturtevant was relaxed, brilliant, and friendly. Morgan was witty, sceptical, playful, diversified in interests, and contemptuous of "unbridled speculation." Bridges was a nonconformist, guileless, mirthful, inventive, and at home in a laboratory.Muller was intense, nervous, intellectually domineering;he gave full rein to his a priori thinking, was impatient, and metabolizedevery new fact into theory.27 By 1915 Muller had established his independence. He had not yet completed his Ph.D. dissertation but he supervised Altenburg's.28He had decided that a new path was needed and that it was to be sought in the nature of the gene and its mutations. The transition can be traced from 1910, when Muller gave a speech-'