1895.] 
Obituary notice of M. Louis Pasteur. 
193 
fermentations, including 1 the putrefactive, are directly due to micro¬ 
organisms, soon received a more important demonstration. The stud- 
of the diseases of fermented liquids led straightway to the practice of 
antiseptic surgery, now so universally applied. Very few years later 
the whole subject of the complete exclusion of micro-organisms was ex¬ 
haustively studied by Sir Joseph Lister, and afterwards by others, to the 
end of the saving of thousands of lives, and the rendering possible of 
many operations which before could hardly be attempted. Pasteur would 
have proceeded to carry out in relation to diseases the great general 
principle that he had established, but now he was forced to change 
somewhat the nature of his inquiry, being urged in 1865 by Dumas to 
undertake the investigation of a disease of silkworms in the south of 
France, which was seriously threatening the silk industry. The exis¬ 
tence of “ corpuscles” in the diseased insects and eggs had already been 
reported, and ( Pasteur, while making a careful investigation of the whole 
disease, directed his chief studies to these. He found that these disease- 
gerins were passed on in the eggs, and invented a plan of testing for 
disease in the breeding moths, which, being practically followed, has 
proved effectual in putting a stop to the plague. After four years spent 
in investigating this subject, Pasteur had a dangerous paralytic stroke, 
in consequence of which, and of the miseries of the Franco-German war, 
which shortly followed, he was debarred for some time from any original 
work. On the end of the war he first betook himself to a study of the 
diseases of beer on the same lines as he had adopted in his previous 
researches on those of wines, and then devoted himself to that field of 
research in which he has won his greatest fame—the study of those 
diseases of animals which might be supposed to originate from virus 
generated by various micro-organisms. Davaine had acquired evidence 
of the dependence of anthrax on the presence of organisms in the blood 
of infected animals, but his work was not well received till Pasteur 
proved its correctness, and then still further extended his researches. 
Most important of all, besides ascertaining the appropriate micro-organ¬ 
isms of several diseases, he found various means of cultivating these 
germs; these he separated, multiplied, and tested their influences under 
various conditions of environment, or after changes had been induced in 
themselves. Most fruitful was the discovery thus made of the possibi¬ 
lity of attenuating, or mitigating gradually, by various culture-processes, 
the virulence of morbific bacteria till they can without harm be intro¬ 
duced into the blood of an animal which under normal conditions would 
raphlly succumb to their effects. And it was shown that some of these 
inoculations had the same effect as vaccination, giving the disease in a 
milder form and along with it protection against a severer attack. 
