IMMUNIZATION BY MEANS OF THE BACTERIOPHAGE 265 



the anti-Shiga bacteriophage cultures, which contain the sub- 

 stance of the bacterial bodies in a dissolved state, shows indeed 

 that these substances undergo profound modifications under the 

 influence of the lysins secreted by the bacteriophagous ultrami- 

 crobe. Nevertheless, these new substances possess a specific 

 immunizing power much more potent than the original substance. 

 The experiments on rabbits, and in particular the results secured 

 in immunization against barbone, demonstrate this beyond pos- 

 sible doubt. 



Prophylactic vaccination against bacillary dysentery by means 

 of cultures of the anti-dysentery bacteriophage is therefore 

 applicable to man. In practice, quite naturally, the prophylactic 

 injections should be performed with a mixture of bacteriophage 

 cultures — anti-Shiga, anti-Flexner, and anti-Hiss. Such a mix- 

 ture would constitute a polyvalent dysentery vaccine. 



The Shiga bacillus is one of the most toxic organisms known, 

 and it may be assumed that the harmlessness of injections of 

 such a culture indicates a general law, whatever may be the 

 bacterium against which the bacteriophage culture is prepared. 

 In order to test this hypothesis, I injected myself, subcutaneously, 

 with half a cubic centimeter of anti-plague bacteriophage. No reac- 

 tion, either general or local, followed. Stool examination made 

 twenty-four hours after the injection showed that the bacterio- 

 phage, equal in virulence to that injected, was present. The 

 inoculation experiment was repeated with anti-typhoid bac- 

 teriophage. G. Eliava repeated it with the anti-staphylococcus 

 bacteriophage, and the same results were secured in both cases. 

 These observations are confirmed in part by another fact, ob- 

 served in several tests, that following the administration of the 

 bacteriophage, either by injection or by ingestion, the bacterio- 

 phage passes in a short time into the intestine. It is eliminated 

 rapidly if it fails to encounter the bacterium against which it 

 has a virulence, that is to say, in an uninfected individual. 

 On the contrary, it grows and maintains its virulence if it is in 

 contact with this bacterium, a condition which, as we have seen 

 in several instances, is produced in an infected environment 

 among animals which remained healthy, or which had been in- 

 fected and were recovered. 



