24 THE BACTERIOPHAGE 



complete, it is attended by the formation of an amorphous mass 

 insoluble in the fluid. If the significance of the term "lysis" 

 is indeed exact in autolysis where there is a partial dissolution, 

 it is by no means the same in " bacteriolysis' ' as this is understood 

 by many authors. Treatises dealing with immunity speak of 

 "bacteriolytic sera/' realizing explicitly that the reactions be- 

 tween antigen and antibody never consist of a digestion. How 

 then, under these conditions, is it possible to have a dissolution? 

 And, in fact, none is ever observed. 



The action manifested by the bacteriophage is wholly different. 

 It comprises phenomena of which the final result is a digestion 

 such as leads to a total dissolution of the bacterial bodies. It 

 is a bacteriolysis in the true sense. At first I considered desig- 

 nating this new phenomenon by a new word, " bacteriophagy" 

 for example, since the word bacteriolysis is often employed to 

 designate processes differing entirely from dissolution. But 

 since the use of too frequent neologisms might distract the reader 

 I have felt that the abuse which has been made of the term 

 " bacteriolysis' ' may be only a transitory one and that the passage 

 of time will soon cause to be forgotten the phenomenon of so- 

 called bacteriolysis without a dissolution of the bacteria. 



To summarize: the phenomena which we will consider have 

 nothing in common with that which is usually designated by the 

 terms "lysis" and "bacteriolysis." Here, the term "lysis" 

 should always be taken in its strict etymological sense of a com- 

 plete dissolution. A bacterial culture in bouillon or a suspension 

 of bacteria in a fluid where bacteriolysis, as we understand it, 

 takes place, completely clears, without residue. The fluid be- 

 comes as limpid as it was prior to its inoculation with culture. 



TECHNIC FOR THE ISOLATION OF THE BACTERIOPHAGE 



All bacteriological laboratories possess the equipment required 

 for the isolation and cultivation of the bacteriophage. For isola- 

 tion a filtering apparatus is indispensable. (I have employed the 

 model of Martin, with Chamberland L 2 and L 3 bougies.) For 

 culture media a peptone bouillon, or such a bouillon incorporated 

 into a 2 per cent agar, is adequate. 



