236 THE BACTERIOPHAGE 



Examination was made of twenty-three specimens of serum, 

 of clot remaining after the decantation of the serum, and of the 

 leucocytic layer on top of this clot, taken from horses harboring 

 in their intestines a bacteriophage active for B. dysenteriae. In 

 no case was a bacteriophage found. In all instances the speci- 

 mens of blood were collected about two weeks after the last 

 injection of toxin or of bacilli. All the specimens of blood ex- 

 amined came from horses furnishing anti-dysentery serum. It 

 was therefore not determined whether the bacteriophage may not 

 pass into the circulation immediately after the injection, espe- 

 cially when living bacteria are used. As a matter of fact the pas- 

 sage of the intestinal bacteriophage into the circulation has been 

 observed in the rat, and in the fowl in cases of septicemia. In 

 all cases the demonstration of the presence, it might be said con- 

 stant presence, in the excreta of the horse of a bacteriophage active 

 for the Shiga bacillus, and the absence of this bacteriophage in 

 the blood, shows in an unquestionable manner that the intestine 

 is the only locality where the bacteriophage normally grows. 

 This fact alone is sufficient to demonstrate the error of the con- 

 ception of Bordet, who has advanced the hypothesis that the 

 bacteriophage is of leucocytic origin. 



THE BACTERIOPHAGE IN THE FOWL 



I have made seventy examinations of the excreta of fowls, and 

 have tested the bacteriophage for virulence against the eight 

 bacterial strains selected. It is needless to give all the results 

 since they were all of the same nature. As examples, the results 

 of only one or two tests in each lot will be given (table 5). 



Nos. 1 and 2 represent chickens living in France in regions 

 free of avian typhosis (12 specimens examined). 



Nos. 3 and 4 represent healthy fowls living in regions where 

 avian typhosis was present (19 other examinations carried out 

 on the eight test bacteria gave comparable results, particularly 

 as regards B. gallinarum). 



Nos. 5 and 6 represent chickens which had recovered from 

 avian typhosis (4 tests made). 



Nos. 7 and 8 represent chickens which died of avian typhosis 

 (8 other tests gave similar results). The bacteriophage was pres- 

 ent but was not virulent for the pathogenic bacillus. 



