BEHAVIOR OF BACTERIOPHAGE IN DISEASE 447 



cases of bacillary dysentery in natives. At no time during the course 

 of the infection did the intestinal bacteriophage show a trace of activity 

 for the Shiga bacillus, either for the stock strain or for those isolated 

 from the stools of the patients. 



A last case, of particular interest, may be presented, for it shows that 

 bacteria may become resistant, acquiring a refractory state, in vivo, as 

 well as in vitro. While undoubtedly such a change in the bacterium 

 may occur within the body, such cases must be very rare, even 

 exceptional. 



AUx Desp .... (fifty-six years). The patient entered the 

 Pasteur Hospital on September 26, 1919. At the time of admission 

 there was a profuse mucous diarrhea with thirty to forty stools a day. 

 Examination of the intestinal contents gave an almost pure culture of a 

 dysentery bacillus presenting atypical characters, as follows: 



Non-motile bacillus. Gram negative. Indol positive. No black- 

 ening of lead acetate agar. No change in neutral red media. Litmus 

 sugar agar media not fermented with any of the sugars. In Barsiekow's 

 medium, maltose and lactose are unchanged, glucose and mannite are 

 turned red. After six transfers on agar it agglutinated to the titre 

 (1 : 6000) with a Hiss agglutinating serum, to 1 :400 with an anti-Flexner 

 serum of which the titre was 1 : 6000, and was not agglutinated at 1 : 20 

 by an anti-Shiga serum. 



In spite of these atypical characters it was, then, a Hiss strain possess- 

 ing weak fermentative properties. 



When secured from the body this bacillus was not affected by a bac- 

 teriophage very virulent for a normal Hiss bacillus, but it became 

 susceptible to dissolution after about a dozen transplantations. It was, 

 then, a bacillus which was refractory to the bacteriophage when re- 

 covered from the body. 



At the same time a strain of bacteriophage was isolated from the stools 

 of the patient. This presented the following virulences: Shiga 0, 

 Flexner + + ; stock culture strain of Hiss + + + + ; ■^. coli + ; the 

 Hiss strain from the patient +. After twelve subcultures of the Hiss 

 strain from the patient the virulence of the filtrate was again tested. 

 Perfect dissolution was secured, showing that the bacillus had lost its 

 resistance by transfers on agar. 



The bacteriophage of the patient was active to a maximum degree 

 against a stock strain of the Hiss bacillus but it was only sHghtly active 

 for the individual strain causing the infection, with which it formed 

 in vitro, mixed cultures indefinitely cultivable. There was likewise in 



