1 6 THE POPULAR SCIENCE MONTHLY 



In 1879, he isolated the microbe of feruncles, and in 1880 those 

 responsible for anthrax and chicken cholera. His studies had demon- 

 strated the fact that every infectious disease thus far investigated was 

 produced by a specific microbe; and, further, that such microbes culti- 

 vated under certain detrimental conditions become attenuated in patho- 

 genic activity, still capable of producing a mild form of disease in an 

 animal inoculated with them, but occasioning immunity to further at- 

 tack. Such cultures of microbes of attenuated virus are vaccines. 



Prophylactic vaccination had, of course, been known in an empirical 

 way prior to this in connection with small-pox. But these researches 

 of Pasteur's afforded the first explanation of that procedure, and in 

 addition cast a flood of light upon the etiology of disease. They firmly 

 established the germ theory, ushered in a scientific practise of medicine 

 and sent to limbo a thousand pious superstitions about demoniacal pos- 

 sessions and the mysterious visitations of an all- wise Providence that 

 doeth all things well. For these researches, the imperial government 

 conferred upon him the cross and cordon of the Legion of Honor. 



During the years of 1880, 1881, 1882, Pasteur gave his attention to 

 hog cholera, rabies, pneumonia in cattle, the bubonic plague, yellow 

 fever and typhoid fever. Of these six diseases he was able to carry to 

 complete success his researches on the first three only. In 1881, a ship 

 having come into Bordeaux from Senegal with several cases of yellow 

 fever on board, he went thither, hoping for a favorable opportunity to 

 study it at first hand. He was not permitted to do so. But his obser- 

 vations convinced him that this fever is not contagious. 



Before the close of 1885, he had isolated the microbe of rabies, pre- 

 pared its vaccine and perfected the method of treatment. This was a 

 disease which caused not merely considerable property loss and suffer- 

 ing, it imbued the popular imagination with a dread but little less than 

 the terror occasioned by a pestilence. 



As despite the researches of hundreds of bacteriologists one may 

 still hear it asserted that rabies is an imaginary disease, some statistics 

 may not here be out of place. Accurate account of 320 cases of persons 

 bitten by mad dogs prior to Pasteur's work in this field, showed a mor- 

 tality of 40 per cent. The first 350 cases treated by his method fur- 

 nished but one death, that of a little girl brought to the hospital in such 

 condition and so late that Pasteur pronounced the case hopeless from 

 the start, and only undertook it for humanity's sake. After the treat- 

 ment had been given in 1,726 cases there had been but ten deaths. 



The conquest of rabies was the last great work accomplished per- 

 sonally by Pasteur. Eeattacked by paralysis in 1888, he conld thence- 

 forth prosecute his ideas only by the labor of other hands. But he had 

 a host of disciples in Europe and America, some of whom had studied 

 under his personal guidance, but many more who, without having seen 



