OBSERVATIONS ON THE PROPERTIES OF BACTE- 

 RIOLYSANTS (D'HERELLE'S PHENOMENON, BACTE- 

 RIOPHAGE, BACTERIOLYTIC AGENT, ETC.) 



PART I' 



WILBURT C. DAVISON 

 Baltimore, Maryland 



INTEODTJCTION 



Twort, d'Herelle and others (Davison, 1922a) have observed 

 that Berkfeld filtrates of stool and other cultures would kill 

 and dissolve young cultures of dysentery and other organisms. 

 The addition of a portion of one of these dissolved cultures, to 

 a new culture would cause it in turn to dissolve. Thus the 

 lytic principle could be transferred from generation to genera- 

 tion. These bacteriolytic filtrates or their subsequent genera- 

 tions are called, interchangeably, bacteriolysants, bacterio- 

 phages and bacteriolytic agents. The process by which these 

 filtrates dissolve dysentery and other organisms is known as 

 d'Herelle's phenomenon or bacteriophagy. 



It has been shown (Davison, 1922a) that agar subcultures of 

 organisms which had been attacked by bacteriophages, con- 

 contained two types of colonies. One was regular and round, 

 resembhng a typical dysentery colony. It was not readily 

 attacked by the bacteriolytic agent. This is the "resistant" 

 type. The other was irregular in outline and is best described 

 as "moth eaten." These colonies were easily dissolved by bac- 

 teriophages and in addition had the property of dissolving other 

 cultures to which they were added. This is the "sensitive" 



' Presented at the twentj'-third annual meeting, Society of American Bac- 

 teriologists, December 29, 1921. From the Department of Pediatrics, of the 

 Johns Hopkins University and the Harriet Lane Home of the Johns Hopkins 

 Hospital, Baltimore, Maryland. 



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