JOHN TYNDALL AND HIS CONTRIBUTION TO THE THEORY OF SPONTANEOUS GENERATION

By LYLE A. WEED, Ph .D., M.D.

INDIANAPOLIS

HE name of Tyndall is well seven to have a formal education and known in the fields of mathe- proceeded to Marburg, Germany, matics, physics and chemistry, where “he graduated in 1850 in the but not so well known in the Philosophical Faculty, taking mathe- fields of biology and medicine. maticsThe as principal subject in viva voce Tonly reference made to Tyndall by most examinations and chemistry and phys- textbooks of bacteriology is to his so- ics’’1 for the two subsidiary subjects. called “Tyndall cone’’ obtained by Thus even with a late start he made a viewing the dispersion of light from the place for himself in educational circles, surfaces of dust particles suspended in and his stay in Germany at this time air. It is not proposed in this article must have brought him in contact with to establish Tyndall as having priority such men as Wohler, Liebig, and prob- in disproving the theory of spontane- ably Pasteur, who were investigating ous generation; but only to show that ferments and the separation of the or- his experiments, which were conclu- ganic from the inorganic. His determi- sive, came at the opportune time to nation to achieve a place in the help swing the balance of opinion in educational world, which so often char- favor of the interpretations accepted acterizes certain types of individuals today, and to review some of his experi- even today; his mental alertness; and ments in bacteriology, which were thor- finally, his contacts with the great men ough, basic, and laid the foundation for of his day, were factors which destined modern bacteriology. him to become a prominent figure in It is not uncommon for a man work- the scientific world. ing in pure science to make funda- While Pasteur, as early as i860, had mental contributions to general biol- performed experiments which he be- ogy, and, indeed, those made by Tyndall lieved disproved the theory of sponta- were made because he was primarily a neous generation, his results were not mathematician, physicist, and chemist. accepted by the rest of the scientific He had very little early formal educa- world, and such men as Needham and tion. His earlier days were spent in the Bastian—who had considerable influ- Highlands of Scotland, out in the coun- ence and a tremendous following—still try away from the crowded districts. He insisted that bacteria did not originate eventually became employed by a rail- from formed masses. The belief was road firm, to do surveying, an occupa- prevalent even in the medical world tion which he found interesting. In that bacteria had little to do with fer- spite of his lack of knowledge of Latin, mentation, putrefaction, and infection he determined at the age of twenty- as the following citations show: The president’s [Huxley’s] discourse, he was beginning to feel the end was . . . was a popular account of the mode near for in the same address he made a of development and form of those minute bid for closing the issue without further structures which the microscope reveals discussion or investigation when he in such prodigious numbers in infusions added: containing organic matter. . . . He ad- duced arguments in favor of the theory If as Professor Tyndall believes, and as that these various bodies are not distinct his experiments seem to show, bacteria organisms, but are different modes of de- and their germs are killed by boiling them velopment of the same substance. . . . for five minutes, nothing remains but for Next morning, Dr. Bastian gave an ac- us to shake hands over the establishment count of his experiments on the contents of the occurrence of “spontaneous genera- of hermetically sealed cases of preserved tion” and the overthrow of the Germ meats, and he reiterated his conclusion Theory of Disease. that the facts he had just elicited were such as to throw on the Biogenists the burden But Tyndall was not a man to give of proof that life did not really, as was up easily and he began to search for a apparently the case, originate de-nouo way to explain why in certain of his ex- from lifeless materials. A somewhat sharp periments boiling for five minutes did passage of arms took place between Dr. not prevent the development of putre- Bastian and Professor Tyndall, each main- faction. Consequently, in the following taining his well-known view point respect- year he reported to the Royal Society ing the atmospheric germ-theory.15 of London a method for preventing the It is more than interesting that at this growth of organisms in infusions by date (1870) men like Huxley were still using temperatures much below the so much in doubt about the origin of boiling point. In a letter to Huxley, species, and no doubt the attitude of then Secretary of the Society, he wrote: such a great thinker and leader had It is known that the prolonged applica- much to do with the rejection of the tion of a low temperature is often equiva- germ theory of disease. In 1876, Bastian lent to the brief application of a higher stated: one; and you may therefore be disposed to conclude that in the experiments here I have set down the names in order of referred to I have substituted time for in- time, and included my own amongst them tensity. This, however, is not the case. The because those mentioned after me have all result depends solely on the manner in confirmed my results with regard to the which the heat is applied. For example, I putrefaction of some fluids in hermetically boil an infusion for fifteen minutes, ex- sealed vessels, from which the air had been pose it to a temperature of 90° Fahrenheit expelled by boiling; the very experiments, and find it twenty-four hours afterward in fact, which Professor Tyndall (like one waking from a three years’ sleep) now en- swarming with life. I submit a second sam- deavors to impeach by his own one hun- ple of the second infusion to a tempera- dred and thirty-nine failures.18 ture lower than that of boiling water for five minutes, and it is rendered perma- Such caustic comment made before the nently barren. British Medical Society six years after- The secret of the success here is an open ward shows that the struggle to demon- one. I have already referred to the period strate the truth of the germ theory had of latency which precedes the clouding of not made much progress as far as Dr. infusions with visible bacteria. During Bastian was concerned, but it is evident this time the germs are being prepared for their emergence into the finished or- against the proponents of the germ the- ganism. They reach the end of this prep- ory: aration successively—the period of latency of any germ depending on its condition as The author first referred to what is regards dryness and induration. This then, known regarding contagion, and then pro- is my mode of proceeding: Before the ceeded to show that the view, which gave latent period of any one germ is com- the best explanation of the co-existent pleted (say in a few hours after the prep- facts is that which regards it as consisting aration of the infusion), I subject it for of minute living organisms, probably of a brief interval to a temperature which albuminous composition, possessing the may be under that of boiling water. Such power of organic development, always re- softened and vivified germs as are on the producing their own kind; capable, under point of passing into active life are favorable circumstances, of preserving thereby killed; others not yet softened re- their vitality for a considerable period; main intact. I repeat this process well but speedily perishing when separated within the interval necessary for the most from these conditions and freely exposed advanced of those others to finish their to the atmosphere. Dr. Carpenter pointed period of latency. The number of unde- out that ... as to contagion he thought stroyed germs is further diminished by it was to be traced to some organic germ, this second heating. After a number of which might, under certain meteorological repetitions which varies with the character or physical conditions, develop into one of the germs, the infusion, however ob- or another of the diseases to which the stinate, is completely sterilized.5 human body was liable. Mr. J. A. Wank- lyn pointed out that . . , as to the nature This process of intermittent heating is of contagion, while not defending the a basic principle applied extensively in chemical theory, he held that, unless they bacteriology and is sometimes today re- could discriminate germs, the germ- ferred to as Tyndallization. theory had no vitality in it. Dr. Mac- In addition to the large amount of Namara was doubtful as to diseases being work that was being done directly on alone capable of reproducing themselves the problem of spontaneous generation, for Scarlet Fever was never found in India, or Cholera in Australia, although both a number of investigators wTere ap- countries were in communication with the proaching the problem indirectly by West and with each other. trying to discover the real nature of the cowpox virus which Jenner had shown In addition to the general comments to be effective in preventing smallpox. made by various investigators and by In an attempt to arrive at the funda- those who did most of their work as mental nature of the substance, Braid- arm-chair philosophers, there were wood and Vacher,12,24 and Maclagan13 many who experimented and reasoned performed a number of experiments at great length to show why the Germ and tried to compare the type of reac- Theory could not be accepted. Richard- tion obtained with the virus with the son,14 in 1870, ten years after Pasteur reactions of numerous chemicals of had started his work on the subject, known constitution. The following carried on extensive investigations quotation from Maclagan,13 in the Brit- which showed his real insight into the ish Medical Journal, shows the differ- subject of immunity as well as infec- ence of opinion that existed concern- tion. His position is well shown by the ing the nature of the virus and clearly following citation from his article “The emphasizes the general antagonism Germ Theory of Disease’’14: The vital or Germ Theory fails (a) in a role in common diseases, but it must the evidence (other than is analogical) not be forgotten that the human mind which it adduces respecting germs of dis- as a whole was still in bondage to the ease, their physical characters, properties, specificities; (b) in tracing a chain of superstition which had ruled civiliza- connection between the origin of the germ tion for centuries. Only a few minds and the origin of the disease; (c) in de- were free enough, broad enough, and fining whether the process set up in the bold enough to believe facts which particular disease and attributed to germs could be easily and simply demon- is fermentative or putrefactive; (d) in ac- strated. Tyndall, however, had been counting for certain best known general trained not only to believe what he facts and symptoms relating to the diseases could see and demonstrate, but to know attributed to germs. Further the theory the value of philosophy, sound reason- does not explain why diseases that are ing, and interpretations of experiments most readily communicable occur, as a with things which could not be seen. rule, only once in the same person; why His researches in heat conduction, heat the same diseases are influenced by age, why the diseases are selective in respect absorption, radiation of heat through to season; why the majority of persons various gases, and the conversion of who suffer from epidemic diseases recover, light energy into sound by the use of and that recovery occurs spontaneously; various gases, were primarily responsi- why if germs are capable of independent ble for his introduction into the Royal multiplication and were the cause of the Society where he came in contact with diseases, there should be recovery at all the more active and prolific minds of when once the body has become infected; or why, if we accept as the cause of the the day. Indeed, it is probable that his diseases independent agents, germs having contacts within the society provided the their own vital existences and mode and stimulus for investigating the theory of force of multiplication in the bodies of spontaneous generation. Having a thor- animals, the diseases which are supposed ough knowledge of the properties of to arise from germs do not increase in- gases and light and having the physical stead of ceasing as some have ceased. apparatus with which to work, it was The physical theory of the origin of the natural for him to apply his funda- communicable diseases, is that the diseases mental knowledge of mathematics, are due to poisons which are organic, but are neither independently reproductive physics, and chemistry, to a problem nor indestructible, nor derived from or- which was profoundly influencing poli- ganisms distinct from the animals in tics, religion, and daily health. He was which the diseases are developed. It ac- convinced that the microscope could cepts that the organic poisons may be col- not be used to solve the question, and loidal and may be transmitted as solid erroneously and pointedly rebuked his particles, on solid substances, or in water, contemporaries for being so superficial or by air, but it holds they are as destructi- in their investigations as to use such an ble as other dead organic matter, and that their action is purely physical on the body. instrument. In his “Note on Dr. Bur- It leaves undecided the hypothesis of fer- don Sanderson’s Latest Views of Fer- mentation. ments and Germs”7 he said: It was at that time difficult for the I made it a special object of my lecture average mind to understand how such before the British Association at Liver- minute plants could play so important pool in 1870 to show how inappropriate it is to invoke the microscope in deciding rubber but it also passes through a stuffing- questions of ultimate structure (page 354). box of sticky cotton-wool. The width of the aperture closed by the Indian rubber And again: secures the free lateral play of the lower It can not be too distinctly borne in end of the pipette. Into two other small mind that between the microscopic limits apertures in the top of the cupboard are and the true molecular limits there is inserted, air-tight, the open ends of two room for infinite permutations and com- narrow tubes, intended to connect the in- binations (page 365). terior space with the atmosphere. The tubes are bent several times up and down, While we now know the microscope, so as to intercept and retain the particles properly used and with proper inter- carried by such feeble currents as changes pretation of the results, could have of temperature might cause to set in be- solved the problem of the structure of tween the inner and outer air. the cause of fermentation, his comment The bottom of the box is pierced, some- shows that he had a better conception times with two rows, sometimes with a of the magnitude of the problem than single row of apertures, in which are fixed, did most of his adversaries. It may well air-tight, large test tubes, intended to con- be that he was thinking of ferments in tain the liquid to be exposed to the action general, as we think of enzymes today, of moteless air. On the 10th September the first case of and, if so, he was about seventy-five this kind was closed. The passage of a con- years ahead of his time since we do not centrated beam of light across it through yet know all the intricacies of energy its two side windows then showed air transfer associated with enzyme action. within it to be laden with floating matter. In his experiment to demonstrate the On the 13th it was again examined. Be- role of dust particles and the contained fore the beam entered and after it quitted organisms in producing fermentation, the case its track was vivid in the air, but putrefaction, and infection, his own within the case it vanished. Three days words best describe the method he em- of quiet sufficed to cause all floating mat- ployed:2 ter to be deposited on the sides and bot- tom, where it was retained by a coating of A number of chambers, or cases, were glycerine with which the interior surface constructed, each with a glass front, its of the case had been purposely varnished. top, bottom, back and sides being of wood. The test tubes were then filled through At the back is a little door which opens the pipette, boiled for five minutes in a and closes on hinges, while into the sides bath of brine or oil and abandoned to the are inserted two panes of glass, facing each action of the moteless air. During ebulli- other. The top is perforated in the middle tion aqueous vapor rose from the liquid by a hole two inches in diameter, closed into the chamber, where it was for the air-tight by a sheet of Indian rubber. This sheet is pierced in the middle by a pin, most part condensed, the uncondensed and through the pinhole is passed the portion escaping, at a low temperature shank of a long pipette ending above in a through the bent tubes at the top. Before small funnel. A circular tin collar, two the brine was removed little stoppers of inches in diameter and one and one-half cotton-wool were inserted in the bent inches high surrounds the pipette, the tubes, lest the entrance of air into the cool- space between both being packed with ing chamber should at first be forcible cotton-wool moistened with glycerine. enough to carry motes along with it. As Thus the pipette, in moving up and down soon, however, as the ambient tempera- is not only firmly clamped by the Indian ture was assumed by the air within the case the cotton-wool stoppers were re- matter of the air. After having remained moved. for four months as pellucid as distilled We have here the oxygen, nitrogen, water, the opening of the back door of the carbonic acid, ammonia, aqueous vapor protecting case, and the consequent ad- and all the other gaseous matters which mission of the mote-laden air, sufficed in mingle more or less with the air of a three days to render the infusions putrid great city. We have them, moreover, “un- and full of life. tortured” by calcination and unchanged That such life arises from mechanically even by filtration or manipulation of any suspended particles is thus reduced to kind. The question now before us is, can ocular demonstration. air thus retaining all its gaseous mixtures, but self cleansed from mechanically sus- This description shows the thorough- pended matter, produce putrefaction? To ness and completeness with which his this question both the animal and vegeta- experiments were conducted, and how ble worlds return a decided negative. closely he came to demonstrating the Among vegetables experiments have cause of putrefaction and fermentation. been made with hay, turnips, tea, coffee, At one point in this communication he hops, repeated in various ways with both describes a microscopic observation of acid and alkaline infusions. Among ani- contaminated material, in which he mal substances are to be mentioned many found a “field of Bacterial life, mon- experiments with urine; while beef, mut- strous in its copiousness.’’ Many types ton, hare, rabbit, kidney, liver, fowl, of bacteria had been previously de- pheasant, grouse, haddock, sole, salmon, scribed and since he had been in com- cod, turbot, mullet, herring, whiting, eel, oyster, have all been subjected to experi- munication with Pasteur prior to this ment. time, it is hard to understand why he The result is that infusions of these sub- did not at once recognize that the fer- stances exposed to the common air of the mentation was due to the presence of Royal Institution laboratory, maintained micro-organisms rather than to “sus- at a temperature of from 6o° to 70 ° Fahr- pended particles.’’ It may be that he enheit, all fell into putrefaction in the used the two terms synonymously. course of from two to four days. No mat- In the light of our present knowledge ter where the infusions were placed, they one might feel that such experiments as were infallibly smitten in the end. The Tyndall’s would have proved conclu- number of the tubes containing infusions sively and beyond any shadow of doubt was multiplied till it reached six hundred, that bacteria did not originate de novo. but none of them escaped infection. In no single instance, on the other For years Tyndall’s work, along with hand, did the air which had been proved that of Schwann, Pasteur, Schroeder, moteless by the searching beam, prove and others was misinterpreted, and the itself, even when raised to temperatures arguments were overshadowed by per- varying from 800 to 90 °, to possess the sonal prejudices until Roberts23 pointed least power of producing bacterial life or out that the experimental results of in- the associated phenomenon of putrefac- vestigators on both sides of the issue tion. The power of developing such life were the same but were being inter- in atmospheric air, and the power of scat- preted in two different fashions. At a tering light, are thus proved to be indis- meeting before the British Medical As- solubly united. sociation he said: The sole condition necessary to cause these long-dormant infusions to swarm Throughout the controversy, Dr. Bas- with active life is the access of the floating tian speaks of the barren tubes and flasks as “failures” or “negative results” and he agents, and by studying the organisms evidently regards the fertile tubes and in pure culture, the idea of the origin flasks as “successful” experiments, having of life de novo vanished in its terminal the force and authority of “positive” re- struggle. John Tyndall was doing much sults. The true view is just the reverse of of the research work discrediting the this, and his misunderstanding on this point makes him blind to the overwhelm- theory at the time of the transforma- ing cogency of the case against him. When tion. In retrospect it is difficult to see the matter is duly considered, it is the that the work of Tyndall is more con- barren flask that has the character of a vincing than that of his predecessors positive result. For what does the experi- fifteen years earlier, but the fact re- menter set himself to do in these experi- mains that the work of Pasteur and his ments? He seeks to destroy by boiling all colleagues had not been accepted as the pre-existing bacteria in these infusions final, especially by Dr. Bastian and his and to leave unimpaired their powers of followers. While Pasteur was not ac- promoting the growth of bacteria. tively engaged in the problem at this Thus we have a proper interpretation time, he appreciated the import of the of the fundamental data which so long controversy and as late as 1875 wrote had been confusing the various inves- Dr. Bastian that he desired to prove tigators; an interpretation which had him (Bastian) wrong because refusal to much to do with lessening the influence accept the germ theory had retarded of Dr. Bastian and his colleagues on medical and surgical progress both public opinion. therapeutically and prophylactically by The relation of bacteria to infection at least fifteen years. He also pointed and disease was coming more and more out that the research of Tyndall was to the foreground and many persons conclusive in disproving the theory of were beginning to forget for the mo- spontaneous generation. An additional contribution of Tyn- ment the question of the origin of mi- dall, not generally recognized, warrants crobic life, and applying their energies attention. In his investigation of the to establishing the causes of certain physical nature of bacteria, which was contagious diseases. The years from reported to the Royal Society in 1877, 1875 to 1890 were as fruitful in bac- he found that the active forms—which teriologic research as any gold rush ever we now call vegetative forms as differ- was in producing material riches. The entiated from spore forms—were sensi- immunization against anthrax in 1881 tive to heat and that “the fully devel- showed that not only were bacteria re- oped bacterium is demonstrably killed sponsible for infectious processes, but at 140° F.” Fhe process known today that it was possible to protect the pa- as “pasteurization,” utilizes a tempera- tients against those invasions. Each year ture range from 140° to 1450 F. It is saw the discovery of a new disease-pro- an indication of the uniqueness of Tyn- ducing organism and investigations dall's ability that at a time when there were so fruitful that there was little were no facilities for pure culture stud- time to quarrel about the issue of ies and only the most meager informa- “spontaneous generation.” tion on the life histories of the organ- By demonstrating the bacterial na- isms, he shotdd have determined the ture of disease and the resistance of lowest temperature which was capable organisms to physical and chemical of destroying the actively growing forms, while working with both vegeta- physics, and chemistry, he had been tive and spore phases in the same mix- more accustomed to the use of the mi- ture. One wonders how much more he croscope and had been equipped with would have accomplished if. in addi- the laboratory facilities which came in tion to his knowledge of mathematics, the following decades.

Ref ere nces 1. Proc. Roy. Soc. London, 55:xxvii-xxxiv, 12. Braid woo d , P. M., and Vache r , F. Con- 1894. tribution to the life history of con- 2. Tyn da ll , J. On the optical deportments tagium. Brit. M. J., 2:265, 1875. of the atmosphere in reference to the 13. Macla gan , T. J. On the nature of con- phenomenon of putrefaction and in- tagium. Brit. M. J., 2:265, 1875. fection. Proc. Roy. Soc., 24:171, 1876. 14. Rich ar dso n , B. W. The germ theory of 3. Tynd all , J. Note on the deportment disease. Brit. M. J., 2:467, 1870. of alkalinized urine. Proc. Roy. Soc., 15. The British Association and the sponta- 25:457> 1876- neous generation question. Brit. M. ]., 4. Tyn da ll , J. Preliminary note on the de- 2:396’ 187°- velopment of organisms in organic 16. Tynda ll , J. Abstract of an article given infusions. Proc. Roy. Soc., 25:503, 1877. before the Royal Society. Brit. M. J., 5. Tyn da ll , J. On heat as a germicide when 1:121, 1876. discontinuously applied, (being a letter 17. Bastia n , H. C. Being a letter to the to T. H. Huxley then Secretary Roy. “Times.” Brit. M. ]., 1:138, 1876. Soc.). Proc. Roy. Soc., 25:569, 1877. 18. Bas tian , H. C. Remarks on a new at- 6. Tynda ll , J. Further researches on the de- tempt to establish the truth of the germ portment of vital resistance of putre- theory. Brit. M. J., 1:157, 1876. factive and infective organisms, from a 19. Bastia n , H. C. A rejoinder to Dr. Tyn- physical point of view. Proc. Roy. Soc., dall’s reply on the development of 26:228, 1877. germs in infusions. Brit. M. J., 1:222, 7. Tynda ll , J. Note on Dr. Burdon Sander- '1876. son’s latest views of ferments and 20. Tynda ll , J. Reply to Dr. Charlton Bas- germs. Proc. Roy. Soc., 26:353, 1877. tian’s remarks on the development of 8. Sander son , J. B. Remarks on the attri- germs in infusions. Brit. M. J., 1:188, butes of the germicidal particles of bac- 1876. teria, in reply to Prof. Tyndall. Proc. 21. Beal e , L. S. A germ theory; remarks of Roy. Soc., 26:416, 1877. some of Tyndall’s observations. Brit. 9. Tyn da ll , J. Observations on hermet- M. J., 1:223, 1876. ically-sealed flasks opened on the Alps 22. Beal e , L. S. Spontaneous generation and (being a letter to Huxley, Secretary the searching beam. Brit. M. J., 1:254, Roy.Soc.).Proc. Roy. Soc., 26:487, 1877. 1876. 10. Tynda ll , J. On Schulze’s mode of inter- 23. Rob erts , W. A word on the origin of cepting the germicidal matter of air. bacteria, and on abiogenesis. Brit. M. Proc. Roy. Soc., 27:99, 1877. J., 1:482, 1876. 11. Tyndall , J. Note on the influence exer- 24. Braidw ood , P. M., and Vach er , F. A cised by light on organic infusions. contribution to the life-history of con- Proc. Roy. Soc., 28:212, 1878. tagion. Brit. M. J., 1:19, 1876.