1895.] Obituary notice of M. Louis Pasteur. 193 



fermentations, including 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 lie 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 tlie south of 

 France, which was seriously threatening the silk industry. The exis- 

 tence of " corpuscles" in the diseased insects and e^^'gs had already been 

 reported, and Pasteur, while niakinuf a cai-efnl investigation of the whole 

 disease, directed his chief studies to these. He found that these disease- 

 germs were passed on in the eggs, and invented a plan of testino- for 

 disease in the breeding moths, which, being practically followed, has 

 proved effectual in putting a stop to the plaijue. 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- Grerman war, 

 which shortly followed, he was debarred for some time from any orio-inal 

 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 liis previous 

 researches on those of wines, and then devoted himself to that field of 

 research in whioh he has won his greatest fame — the study of those 

 diseases of animals whicli nnVht be supposed to oritrinate from virus 

 generated by various micro-organisms. Davaine had acquired evidence 

 of the dependence of anthrax on the presence of or^•anisms in the blood 

 of infected animals, bub 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 cultivatin<>- 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 disco veiy thus made of the possibi- 

 lity of attenuating, or mitigating gradually, by various culture-processes 

 the virulence of morbific bacteria till thej^ can without harm be intro- 

 duced into the blood of an animal which under normal conditions would 

 rapidly 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. 



