CENTURY'S PROGRESS IN SCIENTIFIC MEDICINE 



in the minds of the other leaders, Pasteur had found a 

 solution. Guided by the empirical success of Jenner, 

 he, like many others, had long practised inoculation ex- 

 periments, and on the 9th of February, 1880, he an- 

 nounced to the French Academy of Science that he had 

 found a method of so reducing the virulence of a disease 

 germ that, when introduced into the system of a sus- 

 ceptible animal, it produced only a mild form of the dis- 

 ease, which, however, sufficed to protect against the 

 usual virulent form exactly as vaccinia protects against 

 small-pox. The particular disease experimented with 

 was that infectious malady of poultry known familiarly 

 as "chicken cholera." In October of the same year 

 Pasteur announced the method by which this "attenu- 

 ation of the virus," as he termed it, had been brought 

 about by cultivation of the disease germs in artificial 

 media, exposed to the air; and he did not hesitate to 

 assert his belief that the method would prove " suscepti- 

 ble of generalization " that is to say, of application to 

 other diseases than the particular one in question. 



Within a few months he made good this prophecy, 

 for in February, 1881, he announced to the Academy 

 that, with the aid, as before, of his associates MM. 

 Chamberland and Roux, lie had produced an attenuated 

 virus of the anthrax microbe, by the use of which he 

 could protect sheep, and presumably cattle, against that 

 fatal malady. 



This announcement was immediately challenged in 

 a way that brought it to the attention of the entire 

 world. The president of an agricultural society, real- 

 izing the enormous importance of the subject, proposed 

 to Pasteur that his alleged discovery should be submit- 

 ted to a decisive public test. He proposed to furnish a 



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