428 THE BACTERIOPHAGE AND ITS BEHAVIOR 



of this bacteriophage in the blood, show in an unquestionable manner 

 that the intestine is the only locality where the bacteriophage normally 

 grows. 



These results have received confirmation by all who have made a 

 study of this type; everyone has demonstrated the habitual presence of a 

 race of the bacteriophage virulent for B. dysenteriae in the intestinal 

 tract of the horse. There is no particular advantage to be gained in 

 citing all of the results reported on this subject, but those of Tomaselh^®* 

 are worthy of particular mention. He followed over a period of time, 

 making repeated examinations, the variations in the virulences of the 

 intestinal bacteriophage in two horses, which, during the period of study 

 were subjected to varied conditions of activity and of food. Briefly, 

 his findings are as follows : 

 When resting in the stable; fed upon dry hay: 



The intestinal bacteriophage showed virulences for: 



B. dysenteriae Shiga + + 



B. dysenteriae Flexner -\- + 

 After a period of excessive labor; fed upon dry hay: 

 The intestinal bacteriophage showed virulences for: 



B. dysenteriae Shiga + + + 



B. dysenteriae Flexner + + + 



B. dysenteriae Hiss + 

 When resting in the stable; fed on green food: 

 The intestinal bacteriophage showed virulences for: 



B. dysenteriae Shiga + + + + 



B. dysenteriae Flexner + + + + 



B. dysenteriae Hiss + + 



B. of Gaertner + 



B. coli + + 

 After heavy labor; fed on green food: 



The intestinal bacteriophage showed virulences for: 



B. dysenteriae Shiga + + + + 



B. dysenteriae Flexner + + + + 



B. dysenteriae Hiss + + + 



B. of Gaertner + 



B. coli + + +* 



* These virulences for B. coli refer to the activity for a laboratory strain of this 

 bacillus. Tomaselli did not test the races isolated upon the strains present in the 

 intestinal tracts of the horses themselves. 



