444 



THE BACTERIOPHAGE AND ITS BEHAVIOR 



Case 3, Victor Ker (five years, chart 3). The dysentery 



was caused by the Shiga bacillus, was of moderate severity, and was 

 contracted by contact with the patient next discussed. When admitted 

 to the Hospital, on the third day of the disease, the intestinal bacterio- 

 phage already manifested an average virulence (+ +) for the stock 

 Shiga strain as well as for the strain isolated from the patient. This 

 virulence increased rapidly and maintained a high value up to the time 

 of complete convalescence (+ + +). It then abruptly disappeared. 



Case 4. Jean Ker (six years, chart 4) . This patient was a 



brother of the foregoing. The general condition was poor when ad- 

 mitted to the Hospital on the third day of the disease. There were 

 from twenty to thirty bloody stools a day ; a severe dysentery due to the 



Shiga bacillus. On the fourth day of the disease there were twenty- 

 four bloody stools. The bacteriophage was feebly active (+) for B. 

 coli and was inactive for the Shiga bacillus. The record is shown in 

 table 61. 



From this time on improvement became more and more marked. 

 The activity of the bacteriophage did not disappear after convalescence 

 had been established. 



In the first three of the cases reported above the dysentery was mild. 

 The bacteriophage was active at the onset, the bacterium did not acquire 

 a resistance, and its growth was quickly suppressed. In the last case 

 there was a struggle and the bacillus acquired a resistance which was 

 finally overcome. The condition of this patient was much more serious. 



Case 5. Lans (seventy years, chart 5). This case il- 

 lustrates an extremely severe dysentery due to the Shiga bacillus. The 

 patient entered the Hospital on the second day of the disease. 



