74 THE BACTERIOPHAGE AND ITS BEHAVIOR 



per cubic centimeter. The bacilli were immediately completely ag- 

 glutinated in the form of fine floccules, clearly visible macroscopically. 



The same experiment was carried out with a bacteriophage active 

 for the staphylococcus. When the dialysate was combined with 

 organisms (Staphylococcus aureus) killed by heating for 30 minutes at 

 60°C. a fine agglutinate immediately formed, the clumps being readily 

 visible macroscopically. 



There is present, then, in a filtrate, aside from the bacteriophage 

 principle, which is inoperative upon killed bacteria, a substance capable 

 of augmenting the surface tension of the bacteria, whether they be 

 living or dead, against which the bacteriophage present in the filtrate 

 possesses the power of bacteriophagy. 



RESUME 



Summarizing the data presented in this chapter the following state- 

 ments can be made. 



There is a principle, very widely distributed in nature, normally 

 occurring in the intestinal contents, which possesses the property of 

 dissolving bacteria. This principle is present in a particularly active 

 form in the intestinal canal and in the excreta during convalescence 

 from a variety of infectious diseases (d'Herelle^^*'). 



The phenomenon which this principle causes, in vitro, in a liquid 

 medium containing a suspension of bacteria susceptible to its action, 

 consists essentially in a dissolution of the bacterial cells. This phe- 

 nomenon of dissolution occurs only with living organisms, the medium 

 best suited to the action being that where the bacterium under con- 

 sideration develops best (d'Herelle''^°). 



Dissolution of the bacteria is accompanied not only by a regeneration 

 of the active agent but by a very pronounced multiplication of the 

 principle. 



The agency responsible for the phenomenon has been termed Bacterio- 

 phage, the phenomenon itself is called Bacteriophagy (d'Herelle^^^) . 



By virtue of the fact that in the course of its action the bacteriophage 

 principle multiplies, the dissolving action can be carried out serially 

 for an indefinite period (d'Herelle^^"). 



Multiplication of the bacteriophage principle takes place whatever 

 may be the number of bacteria present in the suspension, or in the 

 culture into which it is inoculated (d'Herelle^-0- 



Although multiplication of the bacteriophage is a process qualita- 

 tively independent of the number of bacterial cells exposed to its 



