408 THE BACTERIOPHAGE AND ITS BEHAVIOR 



Shiga-bacteriophage suspension, when, as we know it did not exist 

 in the Shiga culture, it must be that its presence is associated with the 

 bacteriophage protobe, suggesting that the latter in some way possesses 

 the power of transforming the toxin of the Shiga bacillus into a sub- 

 stance possessing at least some of the properties of an antitoxin. 



The reader will do well not to hastily assert the utter impossibility 

 of this before he has read what is to be said with reference to bacillary 

 dysentery in the remainder of this text. I may say here that the 

 following facts seem to favor this hypothesis. 



I have found^-^ that a suspension of the Shiga-bacteriophage is, im- 

 mediately after bacteriophagy, as toxic (sometimes even more toxic) 

 as a normal culture of Shiga bacilli of the same strain as that which 

 was dissolved. As the bacteriophage suspension ages, this toxicity 

 diminishes, and after about a month with some strains it is almost 

 zero, with others very greatly reduced. On the other hand we know 

 that the dysenteiy toxin is very resistant. If the toxin is destroyed 

 in the presence of the bacteriophage it can only be through the action 

 of the latter. Furthermore, under certain circumstances, suspensions 

 which have become atoxic protect the rabbit against a fatal dose of 

 toxin. 



I have observed that antibacteriophagic sera show a higher anti- 

 phylactic value when the animals have been "immunized" with old 

 bacteriophage suspensions, — those which have become atoxic. The 

 serum of a rabbit which has received injections of fresh, toxic, suspen- 

 sions possesses a less marked antiphylactic property than does that 

 of another rabbit, prepared by the same number of injections of the 

 same suspension when it is 20 to 30 days old. 



All of this seems to indicate that there must be in the bacteriophage 

 suspensions antitoxic principles elaborated through the action of the 

 bacteriophage protobes. 



11. THE OPSONIC ACTION OF BACTERIOPHAGE SUSPENSIONS 



In concluding this discussion of the antigenic nature of the bacterio- 

 phage I will present the results of the experiments performed with 

 Eliava on the question of the opsonic action manifested by suspensions 

 of the bacteriophage. ^^^ 



In the following experiments the opsonic power has been deter- 

 mined by the method of Wright and Douglas, making a mixture of 

 one part of the fluid of which the opsonic action is to be measured, one 

 part of a suspension of leucocjiies, and one part of a suspension of the 



