264 THE BACTERIOPHAGE 



of a cubic centimeter of a culture of the anti-Shiga bacteriophage. 

 The antitoxic immunity is established six days after the injec- 

 tion and persists for at least three months. 



In an experiment of this kind there can be no question of the 

 nature of the process. The bacteriophage as a living being can 

 not be the cause of the immunity. The responsible agent must 

 be the soluble principles contained in the culture medium. 7 



Before undertaking experiments on man I had to assure myself 

 that the administration of cultures of the anti-Shiga bacterio- 

 phage caused no reaction. First, I ingested increasing quantities 

 of the cultures, aged from six days to a month, from one to thirty 

 cubic centimeters, without detecting the slightest malaise. Three 

 persons in my family next ingested variable quantities several 

 times without showing the least disturbance. I then injected 

 myself subcutaneously with one cubic centimeter of a forty-day 

 old culture. There was neither a local nor a general reaction. 

 In all the cases, twenty-four hours after the ingestion or after 

 the injection, I was able to isolate from the stools a bacteriophage 

 possessing for the Shiga bacillus an activity equal to that of the 

 ultramicrobe administered. More recently G. Eliava has re- 

 ceived by subcutaneous injection 5 cc. of a culture of the anti- 

 Shiga bacteriophage aged thirty days. No reaction, local or 

 general, followed. 



It is known that the subcutaneous injection of Shiga bacilli, 

 killed by any procedure whatsoever, can not be performed be- 

 cause of the extremely violent reaction^ produced, and which 

 are due to the toxicity of the germ. This is precisely the reason 

 that vaccine prophylaxis is not applied to dysentery as it is in 

 the case of typhoid. The absolute innocuity of injections of 



7 Several immunizing experiments with the bacteriophage for B. typhosus 

 and for the paratyphoid organisms have been performed upon laboratory- 

 animals, both rabbits and guinea pigs. In all cases these showed a perfect 

 immunization; — 'provided it is permissible to employ the word immuniza- 

 tion when the process is carried out in refractory animals. 



Not attributing any value to experiments of this type I have not included 

 them in the monograph. In all cases the bacteriophage administered, 

 either when given by subcutaneous injection or by the buccal route, has 

 been isolated a few hours later from the intestinal tract. 



