BACTERIA SUSCEPTIBLE TO BACTERIOPHAGY 261 



IJ^. B. suhtilis 



I have isolated a race of the bacteriophage virulent for B. suhtilis 

 from the stools of a patient sick with dysentery. The virulence was 

 high. After 6 hours at a temperature of 37^C. dissolution was complete 

 when it was added to a slightly turbid suspension prepared from a 

 bacillus grown from 12 to 14 hours on agar. Within 12 to 15 hours after 

 the dissolution was complete a secondary culture began to cloud the 

 medium. When spread upon agar characteristic plaques developed.^^^ 



15. Vibrio cholerae (Vibrio comma) 



Of about 100 cases of cholera which I studied in Indo-China I have 

 seen only one which recovered. 



In none of the fatal cases have I been able to demonstrate a bacterio- 

 phage virulent for the cholera vibrio. In the single convalescent which 

 I have seen a filtrate of a stool taken at the moment when the symptoms 

 improved added in the amount of 0.25 cc. to 10 cc. of a suspension of 

 cholera vibrios did not "apparently" cause bacteriophagy, but when 

 spread on agar immediately after the addition of the filtrate there 

 appeared, after incubation, about 50 plaques which had a diameter of 

 about 2 mm. and which were perfectly characteristic. The bac- 

 teriophage was therefore present in the stools. In spite of numerous 

 attempts I have not been able to cultivate it serially .^^^ It is interesting 

 to discover the reason for this failure. 



Jotten^^^ has isolated a bacteriophage from an old culture of the 

 cholera vibrio. 



Meissner,^^^ working in the laboratory of Prausnitz, has isolated a 

 bacteriophage virulent for Vibrio cholerae and for the Tor vibrio from 

 the peritoneal exudate of a guinea-pig which had previously received an 

 intraperitoneal injection of a mixture of Vibrio cholerae, the Tor vibrio, 

 and an anti-cholera serum. 



In another attempt Meissner obtained a bacteriophage by the same 

 method injecting the Tor vibrio alone. At the beginning the virulence 

 was weak but after a few passages a complete dissolution of a suspension 

 was obtained with a dilution of 10~^. Dissolution was complete after 

 12 to 15 hours, but at the seventeenth hour a secondary culture ap- 

 peared which rapidly clouded the medium. At the twenty-fourth hour 

 the turbidity was practically the same as that of a control culture. 



This author has also obtained a virulent bacteriophage by combining 

 in vitro a mixture of the peritoneal exudate of a guinea-pig (obtained 



