Siipplcme?it to "Nature" December 23, 192: 



■ 



Meanwhile, in Paris, Pasteur was advancing from 

 his knowledge of the putrefying of milk with Bacterium 

 lactis to the general study of putrefaction as a state of 

 fermentation caused by the living dust in the air. 

 Liebig had thought of putrefaction as a chemical de- 

 generation : Pasteur thought of it as a vital process. 

 It was more than a result of death : it was the act of 

 life. By 1859, the year of publication of " The Origin 

 of Species," he was in the thick of the fight over the 

 origin of life. He in France, and Tyndall in England, 

 proclaimed and proved the truth of " the germ theory " : 

 that was our phrase for Pasteur sixty years ago, 

 because the notion of putrefactive bacteria was new to 

 us. This controversy, in scientific and non-scientific 

 society, lasted long. In April 1864 Pasteur lectured 

 at the Sorbonne to all Paris : he reviewed and demon- 

 strated his work ; he answered his critics : " I have 

 excluded from my flasks of organic fluids, and am still 

 excluding from them, the one thing which is past man's 

 making : I have excluded from them the germs which 

 float in the air, I have excluded from them life." 

 Finally, he put in very short words the meaning of it 

 all — " La vie c'est le germe, et le germe c'est la vie." 



In 1862 Pasteur had noted the presence of germs in 

 ammoniacal urine, such as occurs with cystitis. In 1863 

 he had told Napoleon III. that his one ambition was to 

 get to know the causes of putrid and contagious diseases. 

 In 1865, when the cholera was raging in Paris, he and 

 Claude Bernard and Deville made many experiments, 

 in vain, on the air of a cholera-ward. That year also, 

 in Glasgow, Lister, sick to death of the old hospital- 

 diseases, set himself, by the " flood of light " which 

 came to him from Pasteur, to prevent wound-infection 

 by dressing wounds with carbolic acid. He was, of 

 course, hampered by the need of wider knowledge, and 

 by undue fear of the " putrefactive bacteria " in the air. 

 Besides, his first carbolic acid was fallible stuff : he 

 would have done as well, or better, with iodine or spirit- 

 But the point is, that he had got hold of principles that 

 are infallible. He had abandoned the fatal notion that 

 putrefaction was caused by the oxygen of the air. 

 Under this notion he had worked hard, in vain, to 

 prevent wound-infection. " But when Pasteur had 

 shown that putrefaction was a fermentation caused by 

 the growth of microbes, and that these could not arise 

 de novo in the decomposable substance, the problem 

 assumed a more hopeful aspect. If the wound could be 

 treated with some substance which, without doing too 

 serious mischief to the human tissues, would kill the 

 microbes already contained in it and prevent the future 

 access of others in the living state, putrefaction might Lie 

 prevented, however freely the air with its oxygen might 

 enter" (Lister's presidential address to the British 

 Association, 1896). On these principles — with many 



changes and improvements of the original method o 

 " Listerism " — all that we call antiseptic and aseptic 

 surgery was founded and built. 



In the war of 1870-71, the French Army suffered 

 heavily from wound-infection. After 187 1, while 

 Lister was practising Pasteurism in Edinburgh, Pasteur 

 was teaching Listerism in the hospitals of Paris, and 

 was defending it against the old school of practitioners. 

 Thus he was one of the founders of modern surgery 

 in France. During this phase of his work he identified 

 Streptococcus alike in boils and in osteomyelitis, and 

 properly said that osteomyelitis is " a boil in a bone." 

 In 1877 came the beginning of Pasteur's threefold 

 work on anthrax, chicken-cholera, and swine-erysipelas. 

 In this colossal work, between 1877 and 1881, 

 Pasteur discovered and proved the use of standardised 

 vaccines. By keeping pure cultures of chicken- 

 cholera, he could bring down their virulence, slowly 

 and steadily, from day to day. By passing this 

 attenuated virus through a succession of small birds, 

 such as sparrows or canaries, he could restore it, point 

 by point, to its full strength. By keeping at a lowered 

 temperature pure cultures of anthrax, he could hinder 

 their sporing, and bring down their virulence. By 

 passing this attenuated virus through a succession 

 of guinea-pigs, he could restore it, point by point, 

 to its full strength. With such methods of attenua- 

 tion and intensification, he was able to standardise 

 diseases in flasks : able to make and to store vaccines, 

 exactly graduated by a fixed scale of their strength. 

 As Roux said of it all, " See how far we have come, 

 from the old metaphysical ideas about virulence, to 

 these microbes that we can turn this way and that 

 way — stuff so plastic that a man can work on it, and 

 fashion it as he likes." 



Finally, in 1880-85, Pasteur discovered and estab- 

 lished the preventive treatment against rabies. He could 

 not isolate and identify the bacteria of the disease : 

 but his work was on the lines of bacteriology. By 

 a long series of experiments, he obtained his virus 

 fixe, his standard of the disease, raised by intensifica- 

 tion to such a point that the latent period in rabbits 

 after inoculation with virulent spinal cord, lasted 

 only for six or seven days, never more, never less. 

 This virus fixe was even stronger than the virus of 

 an ordinary case of rabies. Moreover, it retained its 

 strength through any number of passages from animal 

 to animal. In brief, he standardised rabies, not in 

 flasks but in rabbits : he shortened its latent period 

 to 6-7 days, and fixed it there. Last of all, as with 

 chicken-cholera, so with rabies, he proved that the 

 spinal cords of rabbits infected with his virus fixe lost 

 virulence, slowly and steadily, point by point, by 

 mere keeping. Thus he was able to preserve and 



