CHAPTER II 



Hypotheses Concerning the Nature of the Bacteriophage 



1. possible hypotheses 



We now know of what the phenomenon of bacteriophagy consists. 

 We know that the agent which causes it exists in the state of invisible 

 corpuscles, and that these corpuscles multiply during the course of their 

 action, solely at the expense of Hving bacteria. 



What can be the intimate nature of these corpuscles? 



Let us first examine the general hypotheses which it is possible to 

 formulate. There are three : namely, 



I. Bacteriophagy may be caused by the presence of a foreign chemical 

 principle, that is to say, a principle not derived from the bacterium which 

 undergoes bacteriophagy. 



II. Bacteriophagy may be effected through the action of a principle, 

 either chemical or living, derived from the bacteria which undergo 

 bacteriophagy. 



III. Bacteriophagy may be caused by a living principle foreign to the 

 bacterium. 



These three major hypotheses cover all possibilities. Let us examine 

 them in turn, and see which of them is acceptable, that is to say, which 

 of them is not contradicted by the facts 



/. Hypothesis oj a chemical -principle foreign to the bacterium 



This hypothesis has been sponsored by Kabeshima.^^* According to 

 this author, there is within the intestinal tract of an animal, a catalyzer, 

 derived without doubt from the leucocytes, which causes the dissolu- 

 tion of bacteria by activating some pro-ferment normally present in these 

 bacteria. 



We can not admit that a chemical principle, whether it be termed 

 catalyzer or enzyme, derived from the tissues of an animal, is able to 

 reproduce at the expense of bacteria, since this imphes the power to 

 transform "bacterium substance" into "catalyzer substance." To 

 adopt this one must admit one of two things, either one must accept 

 such a transformation and endow the catalyzer with the power of assimi- 



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