INDIAN NATIONAL LIFE 85 



the first instance contained nothing living, and to shield from 

 the liquids which are placed in the vessels that are used 

 the access of all germs from outside under those con- 

 ditions neither fermentation, nor putrefaction, nor any change 

 of that kind ever took place. Then Pasteur thought that 

 disease, like putrefaction and fermentation, was probably the 

 work of organisms which had access to the human body. 

 And he began to realize his desire to investigate disease. 

 The first disease that he took up was one that afflicted sheep, 

 known as anthrax or charbon, and Jalso as wool-sorter's disease 

 because it is one which can be communicated to humanity. 

 He very soon found that a new organism was evident in 

 the blood of infected animals"which was not in healthy blood, 

 and by taking blood from these infected animals and inoculat- 

 ing healthy animals with it he was very soon able to prove 

 beyond all doubt that the transmission of the disease from 

 one animal to another depended upon the communication 

 of the germ. 



The next disease was one affecting fowls, and he found 

 the same thing : that in chicken cholera the disease was ac- 

 companied always by the presence in the blood of a germ, 

 which was the means of transmitting the disease to another 

 animal. Then he found out, by what many people would 

 call mere accident the accident that only men of genius can 

 use something very much more important, viz. that if you 

 kept the active germ it lost virulence and after a certain 

 number of days, if introduced into healthy animals, would 

 produce the disease in a mild form. And he found that when 

 an organism of that kind, one whose potency had been 

 weakened, was injected into the healthy animal not only 

 did the animal have a mild attack, but it became immune 

 to the influence of the active organism. He discovered, in 

 fact, the principle of treatment now so well known and so 

 widely practised, that of preventive inoculation or vaccination, 



