NATURE OF BACTERIOLYSANTS 503 



ABSENCE OF GELATIN LIQUEFYING ENZYME IN BACTERIOLYSANTS 



AND CULTURES OF "SENSITIVE" AND " NORMAL" STRAINS OF 



BACT. DYSENTERIAE (fLEXNER Y, HISS AND RUSSELL) 



As shown in table 16, gelatin was not liquefied by a bacterioly- 

 sant nor by cultures or "moth eaten" colonies of a "sensitive" 

 strain of Flcxner bacilU nor by regular colonies of a normal 

 strain. 



SUMMARY 



"Moth eaten" or "sensitive" colonies were obtained in sub- 

 cultures of dysentery bacilli which had been attacked by a bac- 

 teriolysant. They were subcultured for forty-two successive 

 generations. The media in which "sensitive" strains of Flexner 

 bacilli were grown, the solutions in which they were washed, and 

 the suspensions of disintegrated or ground up "sensitive" 

 baciUi, were all strongly bacteriolytic. In agar subcultures of 

 old laboratory and freshly isolated normal strains of Flexner 

 bacilh "irregular" colonies were occasionally found, which 

 resembled the "moth eaten" colonies of "sensitive" strains. 

 Filtrates of peptone water cultures of normal strains and ex- 

 pecially of their "irregular" colonies, were shghtly bacteriolytic. 

 B, subtiUs was not bacteriolytic for Flexner bacilli. Trypsin 

 was not bacteriolytic and bacteriolysants and "sensitive" and 

 "normal" strains did not liquefy gelatin. 



CONCLUSION 



It would seem possible that the lytic principle in d'Herelle's 

 phenomenon is an enzyme. This enzyme is not trypsin. A small 

 amount of the lytic principle is contained in, or produced by, 

 normal strains of Flexner bacilli which have been out of contact 

 with the human body for many years. It is possible that the 

 amount of the bacteriolytic enzyme produced by a culture can 

 be increased by aging, by growth in special media or by contact 

 with external influences such as intestinal secretions, tissue 

 extracts, leucocytes, etc. The action of these external influences 

 is probably to favor the develoment of lysogenic organisms at the 



