516 THE BACTERIOPHAGE AND ITS BEHAVIOR 



diagnosis established B. gallinarum as the causative agent. The 

 50 survivors, of which half were already affected, received one intra- 

 muscular injection of 2 cc. of a suspension of bacteriophage virulent 

 for the pathogenic bacterium. During the three following weeks 

 there were 8 deaths, and then the epizootic again broke out with its 

 original vigor. The 22 survivors received a second injection. The 

 disease stopped permanently. 



Observation 2. Enzootic due to B. gallinarum. 



There had been from 1 to 2 deaths per day. The 160 survivors 

 received an injection of 1 cc. of the bacteriophage suspension. The 

 mortality was arrested, only to later break out again. Four weeks 

 after the first, a second injection was given. The enzootic then stopped 

 permanently.* 



Observation 3. Enzootic due to B. gallinarum. 



Within the past year there had been 250 deaths. The 150 survivors 

 were divided into three lots, the animals comprising the different 

 groups receiving 2 cc, 1 cc, or 0.5 cc. of the bacteriophage suspension. 

 The enzootic was suddenly arrested from the day of the injection. 

 None of the animals died during the 6 months following. 



Observation 4- Enzootic due to B. gallinarum. 



This occurred in a brood of chicks. It had lasted for 4 weeks, with 

 from 1 to 4 deaths per day. Each of the 80 survivors (out of an original 

 150) received an injection of 1 cc. of the bacteriophage suspension. 

 There were 4 deaths on the day of the injection, 2 on the next day, 

 and then the enzootic permanently disappeared. 



Observation 5. Enzootic due to B. gallinarum. 



The pullets had received a previous injection of an anti-gallinarum 

 serum, but no effect upon the mortality had been observed. The 300 

 survivors received an injection of 1 cc of bacteriophage suspension. 

 The enzootic stopped at once and did not recur. 



Observation 6. Epizootic due to B. gallinarum. There had been 

 3 to 4 deaths per day. One cubic centimeter of a bacteriophage sus- 

 pension was injected into each of the 150 survivors. The disease dis- 

 appeared immediately and permanently. 



Observation 7. Epizootic due to B. gallinarum. 



Of 110 pullets 30 had died within the past 2 weeks. Among the 

 80 survivors, 40 received an injection of an anti-gallinarum serum, 



* "Arrest" of the epizootic or enzootic means that from the time indicated 

 none of the animals died. This is not a relative measure of effect, but an absolute 

 value. 



