100 THE BACTERIOPHAGE AND ITS BEHAVIOR 



found in the liquid in a "discontinuous" state, that is to say, in the form 

 of corpuscles (d'Herelle^^^). 



A bacteriophage filtrate is then, simply a suspension of bacteriophage 

 corpuscles (d'Herelle^^"). 



Each plaque is a colony of bacteriophage corpuscles derived from a 

 single corpuscle (d'Herelle^^"- ^^^). 



The phenomenon of bacteriophagy leads to the same results upon 

 solid media as in fluid media. There is a dissolution of the bacterial cells 

 and a multiplication of the bacteriophage corpuscles (d'Herelle^^"- ^^0- 



As a result of the mode of action of the bacteriophage corpuscles, the 

 enumeration of the corpuscles present in a suspension may be accom- 

 plished in two different ways, by the method of dilutions and by that 

 of counting the plaques (d'Herelle,^^"' ^^2- ^^^ and following). 



