484 WILBTJKT C. DAVISON 



An eighteen-hour peptone ^vater culture of normal Flexner 

 bacilli was kUled by being heated to 60 to 65°C. for one hour 

 (table 5). A bacteriolysant was then added to this dead culture 

 and the preparation incubated twenty-hour hours at 37°C. and then 

 filtered. This filtrate would not produce macroscopic lysis, but 

 subcultures of the dysentery bacilli to which the filtrate was added 

 contained a few "sensitive" colonies so that a certain amoimt of 

 lytic activitj^ was probably present. However this amount was 

 less than that contained in a bacteriolysant after "passage" 

 through sterile peptone water and almost negligible when com- 

 pared with the bacteriolytic activity of a bacteriolysant after 

 "passage" through a five culture of Flexner bacilli (table 5). 

 The sUght amount of bacteriolytic activity that this filtrate con- 

 tained is probably due to the fact that there was sufficient of the 

 original bacteriolysant present to cause the production of "sensi- 

 tive" colonies. The fact that "passage" through a dead culture 

 reduced the bacteriolytic activity of the bacteriolysant more 

 than "passage" through the same amount of sterile peptone water 

 suggests that the dead bacteria may have adsorbed the lytic 

 principle in much the same way that kaoUn adsorbs enzymes. 



THE EFFECT OF THE REACTION OF THE MEDIA IN WHICH DYSENTERY 

 BACILLI WERE GROWN, ON THE DEGREE OF LYSIS PRO- 

 DUCED IN A CULTURE BY A BACTERIOLYSANT 



Flasks of 1 per cent peptone water, to which phenol-sulphone- 

 phthalein was added, were adjusted to each of the following 

 reactions: pH 6.0, 6.6, 7.1, 7.4, 7.7, 8.0 and 8.2. Two cubic 

 centimeters of the media at each reaction were placed in several 

 tubes and these were sterihzed in the autoclave. These tubes 

 were then inoculated with Flexner dysentery bacilli. After 

 four to twenty-four hours' incubation, bacteriolysants were 

 added and the degree of lysis produced was noted. As may be 

 seen in table 6, cultures whose initial pH was 8.0 and 8.2 were 

 lysed somewhat more completely than cultures whose reactions 

 were from pH 6.0 to 7.7. 



