394 THE BACTERIOPHAGE AND ITS BEHAVIOR 



explanation for our results. It is probable that in our experiment a 

 few of the corpuscles resisted the action of the antiserum — and in al- 

 most equal numbers in the three tubes, since although the number of 

 corpuscles varied in the different tubes, the quantity of antiserum va- 

 ried likewise in the same proportion. These sero-resistant corpuscles 

 parasitized the nearest bacteria and reproduced, and thus were the 

 origin of a sero-resistant line which ultimately provoked a complete 

 bacteriophagy. 



I do not beHeve that it is necessary to discuss further this question 

 of destruction or inhibition. No one can longer have any real doubt 

 on the point, for we have seen in an earher paragraph that the experi- 

 ments of a great many workers agree in showing that the inactivation 

 brought about by an antiserum is very frequently hmited to a single 

 virulence, the other virulences remaining intact. Manifestly, under 

 such circumstances, the bacteriophage protobe can not be destroyed; 

 it can be but an inhibition. 



The possible objection that the obvious inactivation of one virulence 

 while another is retained may be due to the fact that the experiment 

 was not performed with pure races of the bacteriophage, but rather 

 with mixtures of different bacteriophages, each being then neutralized 

 specifically by its antiserum, is valid for the experiments of Otto, but 

 it can not hold for either those of Wolff or those which I have reported, 

 for in both instances the races of the bacteriophage used were certainly 

 ultrapure. 



In what way does this inactivation of virulence occur? As a matter 

 of fact, is the action of the antiserum on the protobe itself or on the 

 bacterium? This it is impossible to answer definitely at the present 

 time. 



A number of authors, among whom Arnold and Weiss-^ may be 

 mentioned particularly, have attempted to show that the ''neutraliza- 

 tion" of a bacteriophage by an antiserum follows a course identical to 

 that of the neutralization of a toxin by an antitoxin. These authors 

 have adopted a method of reasoning which appears again and again 

 throughout the study of the bacteriophage. They have selected a 

 single, relatively unimportant fact, found that it has an analogy in 

 some other phenomenon, and have generalized from this fact without 

 taking into consideration all of the other facts which inherently contra- 

 dict their deductions. Furthermore, in the case of the authors men- 

 tioned, their method of "titrating" the bacteriophage is so inadequate 

 that it does not permit a satisfactory study of the phenomenon. 



