BACTERIOPHAGE AS AN ANTIGEN 415 



The repeated injection of an animal with a bacteriophage suspension, 

 instead of immunizing the animal, may sensitize it, inducing the anti- 

 phylactic state (d'Herelle^^O- 



This state of antiphylaxis may be sufficiently pronounced to cause 

 the animal to lose its naturally refractory condition for a given bacterium 

 (Hauduroy29s). 



Suspensions of the bacteriophage possess a powerful opsonic action 

 (d'Herelle and EHava^-^). 



