THE VACCINE OF SPLENIC FEVER. 233 



land had thus at their disposition several cows which 

 had recovered from splenic fever, and which had ex- 

 perienced in their attack all the worst symptoms. At 

 the places of inoculation enormous swellings were 

 formed, which extended to the limbs, or under the 

 abdomen, and which contained several quarts of 

 watery fluid. . The fever had been intense, and at one 

 time death had appeared imminent. When these 

 cows recovered they were reinoculated with great 

 quantities of virulent virus. Not the least trace of 

 disease showed itself, even in cases where the inocula- 

 tion was performed after an interval of more than a 

 year. 



The question was solved ; splenic fever, like most 

 of the virulent diseases which it has been possible to 

 study, was non-recurrent. The immunity obtained 

 has a long duration. With that valiant ardour 

 which always urges him on, Pasteur next proposed 

 to examine the vaccine of splenic fever. In view 

 of these new investigations, which would require 

 long and careful labours, and which necessitated a 

 certain amount of medical knowledge, Pasteur asso- 

 ciated with himself, in addition to M. Chamberland, 

 a young savant, now a doctor of medicine, M. 

 Roux. 



Following the rigorous course of his deductions, 

 Pasteur naturally turned to the oxygen of the air in 

 his attempts to modify the virulence of the splenic 



