166 LOUIS PASTEUR 



might squirm through. Paul Bert, had claimed 

 that animals might be given anthrax if inoculated 

 with blood subjected to compressed oxygen which 

 could be seen to destroy the bacteria of this disease 

 as well as the septic vibrios which are sometimes 

 associated with it. It must be something beside 

 the bacilli, he argued, that caused the disease. The 

 explanation, as Pasteur showed, is that although 

 oxygen may destroy the bacteria it is not delete- 

 rious to the spores. Bert visited Pasteur's labora- 

 tory and became convinced of the correctness of 

 this interpretation and acknowledged his mistake, 

 acting, as Pasteur observed, "like a loyal French- 

 man." 



Anthrax is a disease which attacks different 

 species of animals with different degrees of viru- 

 lence. Rabbits and guinea pigs are very suscepti- 

 ble; rats and dogs are relatively immune to it. 

 Fowls ordinarily do not take the disease. What is 

 the reason for the immunity of the fowl? It oc- 

 curred to Pasteur that since the temperature of 

 fowls is several degrees higher than that of mam- 

 mals, it might be that the temperature of the fowl's 

 blood is unfavorable to the development of the 

 anthrax bacillus. To test this supposition Pasteur 

 immersed a hen in a bath of cold water in order to 



