BACTERIOPHAGY IN A FLUID MEDIUM 



43 



planted with a concentrated suspension of Shiga bacilh, sufficient being 

 added to give a normal suspension of 250 million per cubic centi- 

 meter. Finally, each tube is inoculated with 0.001 cc. of the bacterio- 

 phage fluid. After 24 hours the appearance of the suspensions shows a 

 certain correlation to the reaction of the medium. The results are given 

 in table 1. 



At the beginning of my studies I stated that bacteriophagy could 

 take place in an alkaline physiological salt solution^'^'^-^''^ Expressed in 

 this manner, it may be that this statement may not be accurate, al- 

 though assuredly under these conditions a very definite, sometimes com- 

 plete, clearing of the medium may be observed. Others (Davison ,i^^ 

 Kabelik,'^^) have also observed this and have attributed, as I had 



done, the bacterial dissolution occurring in saline under the influence 

 of the bacteriophage, to a typical bacteriophagy. We will return to 

 this phenomenon later and consider the correct interpretation. 



Maitland^2 j^^g^ however, shown that bacteriophagy may take place 

 in a medium very poor in food materials, such as physiological saline 

 containing but 1 per cent of bouillon. I have substantiated this; 

 under such conditions bacteriophagy undoubtedly occurs. 



Reaction of the medium 



Unquestionably, alkalinity of the medium affords the most favorable 

 reaction for accompHshing the phenomenon of bacteriophagy. But 

 if an attempt is made to define more precisely the exact degree of 



