CHAPTER III 



• . The Nature of the Bacteriophage 



1. statement of the problem 



All of the arguments which have been advanced by the supporters 

 of the different theories discussed in the preceding chapter are indirect 

 arguments based upon circumstances of time or place. But it is not 

 the place where a being is found, nor the circumstances which surround 

 its discovery, that determine what must or must not be the intimate 

 nature of the being. 



Statements to the effect that under natural conditions the bacterio- 

 phage principle is found in some strains of bacteria; that the principle 

 is encountered in the peritoneal cavity, in the blood, in the pus of 

 abscesses, or in any tissue whatsoever, mean simply what they say. 

 Can such things prove, beyond possible contradiction, whether the 

 principle is a ferment or a living being? 



If it can be definitely proved,- — a proof which has not yet been 

 adduced,^ — that the bacteriophage can act only upon a bacterium during 

 the process of bacterial division, we will have additional information 

 it is true, but will this exclude the possibihty of the living nature of the 

 principle? Would the fact that the moment of division is the critical 

 moment for the cell exposed to the principle, and it seems that this is 

 true for all cells exposed to ultraviruses, imply that the principle is 

 inert?* 



All of these things may be true, they say, nevertheless such and such a 

 fact ''fits in" better with this or that hypothesis. It is a question of 

 evaluation, for one author the fact in question favors the hypothesis 



* Naturally we need not discuss those strange arguments based on facts which, 

 according to some authors, are incompatible with its living nature, such as the 

 fact that it is flocculated by distilled water containing very small quantities of 

 acid, or that it presents the characters of colloids. These authors have doubtless 

 reflected that many bacteria are flocculated by acids, and that it is, therefore, 

 simply a question of more or less. Doubtless they recall that the colloidal state 

 is the one peculiar to all living matter. They have certainly determined whether 

 the bacteriophage must be a colloid or a crystalloid, for there is no third state. 

 Would they have needed to recognize in it the properties of crystalloids to enable 

 them to believe that it might possibly be living? 



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