VIRULENT DISEASES. 209 



This invulnerability had very much struck Pasteur 

 and his two assistants, Joubert and Chamberland. 

 What was it in the body of a fowl that enabled 

 it to thus resist inoculations of which the most in- 

 finitesimal quantity sufficed to kill an ox? They 

 proved by a series of experiments that the microbe 

 of splenic fever does not develop when subjected to 

 a temperature of 44 Centigrade. Now, the tempe- 

 rature of birds being between 41 and 42 degrees, 

 may it not be, said Pasteur, that the fowls are 

 protected from the disease because their blood is too 

 warm not far removed from the temperature at which 

 the splenic fever organism can no longer be culti- 

 vated ? Might not the vital resistance encountered in 

 the living fowl suffice to bridge over the small gap 

 between 41-42, and 44-45 degrees? For we must 

 always allow for a certain resistance in all living 

 creatures to disease and death. No doubt, life to 

 a parasite in the body of an animal would not be 

 as easy as in a cultivating liquid contained in a glass 

 vessel. If the inoculating microbe is aerobic, it can 

 only be cultivated in blood by taking away the oxygen 

 from the globules, which retain it with a certain 

 force for their own life. Nothing was more legitimate 

 than to suppose that the globules of the blood of the 

 fowl had such an avidity for oxygen that the fila- 

 ments of the splenic parasite were deprived of it, and 

 that their multiplication was thus rendered impossible. 



