HYPOTHESES CONCERNING NATURE OF BACTERIOPHAGE 311 



Those hypotheses, of whatever nature they may be, which attempt to 

 attribute the phenomenon of bacteriophagy to the introduction into 

 the first suspension of the series of some "chemical principle" foreign 

 to the bacterium which undergoes lysis, whether this principle is desig- 

 nated by the name catalyzer, soluble ferment, or by any other name, is, 

 from a mathematical point of view absurd, and consequently, can not be 

 accepted. 



II. Hypothesis of a principle derived from the bacterium 



Expressed in this way, in general terms, this hypothesis admits of four 

 solutions. Manifestly, in the first place, the principle may be an 

 abnormal product elaborated by the bacterium, in which case it can only 

 function as a pathological ferment, or it may be a normal physiological 

 product present in all bacteria. 



Upon further analysis each of these two concepts may be interpreted 

 in two different ways. The principle elaborated by the bacterium, 

 whether it be physiological or pathological, may be assumed to be either 

 inert or living. 



The general hypothesis, therefore, consisting of the concept that bac- 

 teriophagy is a phenomenon of dissolution caused by a principle elabo- 

 rated by the bacterium itself, is open to any one of the four solutions : 



A. The principle is abnormal and inert. If this is true it can only be 

 an "autolysin" resulting from a vitiation of the bacterial metabolism. 



B. The principle is abnormal and living. In this case it can only be a 

 fragment of the bacterium freed at the moment of dissolution, and inci- 

 dentally it must be a fragment which retains its capacity to multiply. 



C. The principle is normal and inert. It is then an autolytic enzyme 

 elaborated by all bacteria. 



D. The principle is normal and living. Here again it must still be a 

 fragment of the bacterium, retaining the property of multiplication, and 

 a normal constituent of all bacteria. 



All of these hypotheses, with the exception of the second, have found 

 supporters. The question of the bacteriophage has stirred up such 

 diverse and singular conceptions that hardly anything can be said 

 which has not had its day. But let us consider these four interpreta- 

 tions, and see how well they accord with the facts. 



A. Hypothesis of an abnormal inert principle. The first to adopt this 

 concept were Bordet and Ciuca.^^-^" Their theory comprised two ideas; 

 first, under the action of some product elaborated by the leucocytes the 

 bacteria undergo a nutritive vitiation leading to their dissolution,^^ 



