VII. 

 RABIES 



IT was in December, 1880, that Pasteur took in 

 hand the study of rabies. It was on July 6, 1885, 

 that he first used on man the protective treatment 

 which he had proved on animals. In a few months, 

 we shall come to the thirtieth anniversary of that 

 event : there ought to be a calendar of the healing 

 art, to remind us of all such days. 



He had discovered, in 1880, how to attenuate 

 the virus of the fowl- cholera. He had discovered, 

 in 1881, how to intensify the virus of anthrax, by 

 inoculating with an attenuated virus a series of 

 newly -born guinea-pigs. The attenuated virus, 

 not strong enough to kill a guinea-pig which was 

 several days old, was strong enough to kill a 

 guinea-pig which was one day old. By passing it 

 through a series of one-day-old guinea-pigs, inocu- 

 lating each of them with the blood of its predecessor 

 in the series, he was able to intensify it, till it was 

 strong enough to kill full-grown guinea-pigs, and 

 even to kill sheep. 



72 



