528 THE BACTERIOPHAGE AND ITS BEHAVIOR 



2, Bablet has shown that the bacteriophage corpuscles are destroyed 

 by preservation for a week in glycerine. We know that this sub- 

 stance exerts no destructive influence on either the diastases or the 

 toxins. It may be assumed, therefore, that in a mixture of bacterio- 

 phage suspension and glycerine the protobes alone will be destroyed 

 while the immunizing substances contained in the medium will remain 

 intact. Starting from this hypothesis, we mixed 0.5 cc. of a suspension 

 of the Barbone-bacteriophage with 9.5 cc. of glycerine. After holding 

 the mixture at incubator temperature (37°C.) for ten days, and after 

 we were assured that the corpuscles were effectively destroyed, we 

 inoculated two steers with this hquid, diluted in 500 cc. of saline. Each 

 steer thus received 0.25 cc. of the original suspension. Tests after 

 forty-five days, respectively with 5 and 50 fatal doses of a culture of the 

 bacterium of barbone, showed that these two animals resisted. They 

 had acquired an immunity in spite of the destruction of the bacterio- 

 phage protobes. 



In the case of experimental barbone the tests were made in a barbone- 

 free region, and the principle which is responsible for the development 

 of the immunity is most probably constituted of the substance of the 

 bacterial cells. The role which the bacteriophage plays here is to 

 dissolve the bacteria, in which condition the bacterial substance is in a 

 state particularly adapted to stimulating the cells of the body which 

 enter into the production of organic immunity. The substance of the 

 bacterial body dissolves in the medium under the influence of the 

 dissolving principle elaborated by the protobes, but it is not present in 

 the same condition as in the body of the living bacterium, for the 

 bacteriophage does not simply produce a disintegration. This is 

 shown by the fact that the culture medium becomes perfectly limpid, 

 whereas the medium remains cloudy when a simple disintegration takes 

 place. As we have seen in several tests, the destruction of the bacterium 

 by the bacteriophage is a process of solution. Indeed, it is rather the sub- 

 stances composing the bacterial body which are dissolved. This process 

 is of necessity accompanied by a change in state. It is, then, not proper 

 to speak of the bacterial substance as the principle which provokes 

 the acquisition of immunity; it is in reality the products resulting from 

 the degradation of the substances composing the bacterial cells which 

 are effective. 



It is obvious that this is yet only an hypothesis, experiment showing 

 only that the principle which provokes the appearance of immunity 

 is not, under the conditions of the experiment, the bacteriophage con- 



