60 THE BACTERIOPHAGE AND ITS BEHAVIOR 



race c, was isolated from the stools of a patient convalescent from 

 Asiatic cholera. The medium was prepared with Liebig's meat ex- 

 tract, containing 0.5 per cent of salt and 1 per cent of peptone. The 

 reaction was adjusted to pH 7.6. 



I. The water-bath was regulated to maintain a temperature of 

 45°C. 



Ten cubic centimeters of a suspension of B. coli, 100 million per 

 cubic centimeter, were inoculated with 0.02 cc. of bacteriophage 

 filtrate. 



After 1 hour the opacity was equivalent to 100 millions per cubic 

 centimeter. 



After 2 hours the opacity was equal to 75 millions. 



After 3 hours the medium was clear; dissolution was complete. 



Control 1 ; the same suspension, but uninoculated with the bacterio- 

 phage. After 1, 2, and 3 hours at the same temperature of 45°C. 

 there was no change. The opacity of the supension remained the 

 same as at the beginning. 



Control 2; bouillon simply seeded with B. coli. After 3 hours at 

 45°C. the medium was clear; throughout a period of 3 hours at this 

 temperature there was no obvious development. 



II. The water-bath was regulated to maintain a temperature of 

 46°C. The conditions were the same as for the preceding; 10 cc. of a 

 suspension of B. coli, 150 million per cc, inoculated with 0.05 cc. of 

 bacteriophage filtrate (a filtrate of the suspension dissolved at 45° in 

 the preceding experiment). 



After 1 hour the opacity was equal to 150 milhons per cubic centimeter. 



After 2 hours the opacity was the same. 



After 3 hours the opacity was equal to 100 million. 



After 3| hours the opacity corresponded to 50 million. 



After 4 hours the medium was clear; dissolution was complete. 



Control 1; bouillon simply seeded with B. coli, without the addi- 

 tion of the bacteriophage. No development occurred within 4 hours. 

 The medium remained as it was at the beginning of the experiment, 

 immediately after seeding. 



Control 2; suspension of 150 millions per cubic centimeter, without 

 bacteriophage. The turbidity was the same after 1, 2, 3, and 4 hours 

 as at the beginning. The culture showed no evidence of bacterial 

 multiplication. 



III. The water-bath was regulated to maintain a temperature of 

 47°C. The procedure was the same as that given above. 



