This was, indeed, a most suggestive experiment, proving that the mere fall of temperature from 42° C. (the temperature of hens) to 38° C. was sufficient to cause a receptive condition; the hen, brought down by immersion to the temperature of rabbits or guinea-pigs, became a victim like them.
Between Sédillot’s enthusiasm and Colin’s perpetual contradiction, many attentive surgeons and physicians were taking a middle course, watching for Pasteur’s results and ultimately accepting them with admiration. Such was the state of mind of M. Lereboullet, an editor of the Weekly Gazette of Medicine and Surgery, who wrote in an account of the Académie de Médecine meeting that “those facts throw a new light on the theory of the genesis and development of the bacillus anthracis. They will be ascertained and verified by other experimentalists, and it seems very probable that M. Pasteur, who never brings any premature or conjectural assertion to the academic tribune, will deduce from them conclusions of the greatest interest concerning the etiology of virulent diseases.”
But even to those who admired Pasteur as much as did M. Lereboullet, it did not seem that such an important part should immediately be attributed to microbes. Towards the end of his report (dated March 22, 1878) he reminded his readers that a discussion was open at the Académie de Médecine, and that the surgeon, Léon Le Fort, did not admit the germ theory in its entirety. M. Le Fort recognized “all the services rendered to surgery by laboratory studies, chiefly by calling attention to certain accidents of wounds and sores, and by provoking new researches with a view to improving methods of dressing and bandaging.” “Like all his colleagues at the Academy, and like our eminent master, M. Sédillot,” added M. Lereboullet, “M. Le Fort renders homage to the work of M. Pasteur; but he remains within his rights as a practitioner and reserves his opinion as to its general application to surgery.”
This was a mild way of putting it; M. Le Fort’s words were, “That theory, in its applications to clinical surgery, is absolutely inacceptable.” For him, the original purulent infection, though coming from the wound, was born under the influence of general and local phenomena within the patient, and not outside him. He believed that the economy had the power, under various influences, to produce purulent infection. A septic poison was created, born spontaneously, which was afterwards carried to other patients by such medicines as the tools and bandages and the hands of the surgeon. But, originally, before the propagation of the contagium germ, a purulent infection was spontaneously produced and developed. And, in order to put his teaching into forcible words, M. Le Fort declared to the Académie de Médecine: “I believe in the interiority of the principle of purulent infection in certain patients; that is why I oppose the extension to surgery of the germ theory which proclaims the constant exteriority of that principle.”
Pasteur rose, and with his firm, powerful voice, exclaimed: “Before the Academy accepts the conclusion of the paper we have just heard, before the application of the germ theory to pathology is condemned, I beg that I may be allowed to make a statement of the researches I am engaged in with the collaboration of Messrs. Joubert and Chamberland.”
His impatience was so great that he formulated then and there some headings for the lecture he was preparing, propositions on septicæmia or putrid infection, on the septic vibrio itself, on the germs of that vibrio carried by wind in the shape of dust, or suspended in water, on the vitality of those germs, etc. He called attention to the mistakes which might be made if, in that new acquaintance with microbes, their morphologic aspect alone was taken account of. “The septic vibrio, for instance, varies so much in its shape, length and thickness, according to the media wherein it is cultivated, that one would think one was dealing with beings specifically distinct from each other.”
It was on April 30, 1878, that Pasteur read that celebrated lecture on the germ theory, in his own name and in that of Messrs. Joubert and Chamberland. It began by a proud exordium: “All Sciences gain by mutual support. When, subsequently to my early communications on fermentations, in 1857—1858, it was admitted that ferments, properly so called, are living beings; that germs of microscopical organisms abound on the surface of all objects in the atmosphere and in water; that the hypothesis of spontaneous generation is a chimera; that wines, beer, vinegar, blood, urine and all the liquids of the economy are preserved from their common changes when in contact with pure air—Medicine and Surgery cast their eyes towards these new lights. A French physician, M. Davaine, made a first successful application of those principles to medicine in 1863.”
Pasteur himself, elected to the Académie des Sciences as a mineralogist, proved by the concatenation of his studies within the last thirty years that Science was indeed one and all embracing. Having thus called his audience’s attention to the bonds which connect one scientific subject with another, Pasteur proceeded to show the connection between his yesterday’s researches on the etiology of Charbon to those he now pursued on septicæmia. He hastily glanced back on his successful cultures of the bacillus anthracis, and on the certain, indisputable proof that the last culture acted equally with the first in producing charbon within the body of animals. He then owned to the failure, at first, of a similar method of cultivating the septic vibrio: “All our first experiments failed in spite of the variety of culture media that we used; beer-yeast water, meat broth, etc., etc....”
He then expounded, in the most masterly manner: (1) the idea which had occurred to him that this vibrio might be an exclusively anaërobic organism, and that the sterility of the liquids might proceed from the fact that the vibrio was killed by the oxygen held in a state of solution by those liquids; (2) the similarity offered by analogous facts in connection with the vibrio of butyric fermentation, which not only lives without air, but is killed by air; (3) the attempts made to cultivate the septic vibrio in a vacuum or in the presence of carbonic acid gas, and the success of both those attempts; and, finally, as the result of the foregoing, the proof obtained that the action of the air kills the septic vibriones, which are then seen to perish, under the shape of moving threads, and ultimately to disappear, as if burnt away by oxygen.
“If it is terrifying,” said Pasteur, “to think that life may be at the mercy of the multiplication of those infinitesimally small creatures, it is also consoling to hope that Science will not always remain powerless before such enemies, since it is already now able to inform us that the simple contact of air is sometimes sufficient to destroy them. But,” he continued, meeting his hearers’ possible arguments, “if oxygen destroys vibriones, how can septicæmia exist, as it does, in the constant presence of atmospheric air? How can those facts be reconciled with the germ theory? How can blood exposed to air become septic through the dusts contained in air? All is dark, obscure and open to dispute when the cause of the phenomena is not known; all is light when it is grasped.”