THE VACCINE OF SPLENIC FEVER. 239 



sixty sheep. Ten of these sheep were not to receive 

 any treatment; twenty-five were to be subjected to 

 two vaccinal inoculations at intervals of from twelve 

 to fifteen days, by two vaccines of unequal strength. 

 Some days later these twenty-five sheep, as well as 

 the twenty-five remaining ones, were to be inoculated 

 with the virus of virulent splenic fever. A similar ex- 

 periment was to be made upon ten cows. Six were to 

 be vaccinated, four not vaccinated ; and the ten cows 

 were afterwards, on the same day as the fifty sheep, to 

 receive inoculation from a very virulent virus. 



Pasteur affirmed that the twenty-five sheep which 

 had not been vaccinated would perish, while the 

 twenty-five vaccinated ones would resist the very 

 virulent virus; that the six vaccinated cows would 

 not take the disease, while the four which had not 

 been vaccinated, even if they did not die, would at least 

 be extremely ill. 



As soon as the agricultural and scientific press 

 had published this programme, and recorded Pasteur's 

 prophecies, several of his colleagues at the Academy of 

 Sciences, startled by such boldness in reference to a 

 subject which had hitherto been enveloped in such 

 profound obscurity, and fearing to see the illustrious 

 company somewhat compromised by these affirmations 

 in relation to problems of physiology and pathology, 

 addressed some observations to M. Pasteur on what 

 they called ' a scientific imprudence.' 



