THE BACTERIOPHAGE IN DISEASE 207 



the feathers roughened, and with the characteristic diarrhea. 

 The appearance is the same as in the fowls which succumb. At 

 this stage of the infection examination of the feces gives results 

 such as: 



B. gallinarum, present in abundance. 



Intestinal bacteriophage, virulent for B. coli -f (in 2 cases) 

 or ++ (in 2 cases); for B. gallinarum (in the four cases). The 

 blood culture was positive in the two cases in which it was done; 

 the blood for culture being taken aseptically by puncture of the 

 crest. 



During the course of the day the condition remains the same 

 as that shown by animals which die. This state is prolonged and 

 the next morning the chicken still appears the same. Examina- 

 tion of the feces at this time shows: 



B. gallinarum present in three cases, absent in one. 



Intestinal bacteriophage virulent for B. coli + + + (4 cases); 

 for B. gallinarum + (in 3 cases) + + + (in 1 case). Towards 

 noon, in one case, in the course of the afternoon in the three others, 

 blood cultures were negative. In three eases a bacteriophage 

 active for B. gallinarum was found in the blood. The blood which 

 was ultrasterile was that of the chicken whose condition was the 

 best at this time and which had shown no pathogenic bacilli in 

 the intestinal tract in the morning. The presence of the bac- 

 teriophage in the blood is extremely transitory. 



On the morning of the third day the animals appeared normal, 

 they drank a great deal, ate some grain, and the diarrhea was 

 less profuse. Examination of the feces showed: 



B. gallinarum absent in the four cases. 



Intestinal bacteriophage active for B. coli + + + (4 cases), 

 for B. gallinarum + + -f- (3 cases) + + + + (1 case). Blood 

 cultures were negative: no bacilli, no ultramicrobes. 



On the fourth day the animals were practically normal. 



In the four chickens which recovered the bacteriophage re- 

 mained active for B. gallinarum for a very long time. After 

 three months it showed the same degree of activity as at the time 

 of recovery. In one of them, in which it has been possible to 

 make an examination after five months, it was still as active as 

 at first. We will see, from experimental observations that this 



