BACTERIOPHAGY IN A FLUID MEDIUM 75 



action, the dissolution of the bacterial cells, a direct result of this 

 multiplication, is complete only within the limits of 1 and 700 million 

 bacteria per cubic centimeter when the bacteriophage principle in- 

 volved possesses a maximum activity. With a greater number of 

 bacteria per cubic centimeter the dissolution is but partial (d'Herelle^-^). 



The minimal quantity of bacteriophage principle necessary to ob- 

 tain dissolution of a suspension or a bacterial culture is, in the more 

 favorable cases, equal to a ten-billionth part of a cubic centimeter 

 (lO-i*^ cc); sometimes even a hundred-billionth part is sufficient 

 (d'Herelle^'i"). 



Bacteriophagy takes place under aerobiosis or anaerobiosis. The 

 temperature extremes are 8 and 4G°C., but for all bacterium-bacterio- 

 phage systems the hmits, as well as the optimum temperature are not 

 identical. The temperature relationships vary, on the one hand, with 

 the bacterial species, and even with the bacterial strain, and, on the 

 other hand, with the race of bacteriophage (d'Herelle^-^). 



Only living and normal bacteria are suited to the phenomenon of 

 bacteriophagy. That is to say, the phenomenon does not take place 

 in the presence of antiseptics, when the amount present is sufficient 

 to modify, in any way, the state of the bacteria (d'Herelle^^''). 



Bacteriophagy may be accompanied by accessory phenomena. The 

 process of multiplication of the bacteria subjected to the action of the 

 bacteriophage principle may exhibit an accelerated rate prior to the 

 phase of dissolution. An initial phase of the reaction may be charac- 

 terized by an agglutination. 



