UBIQUITY OF BACTERIOPHAGE 



419 



all of the bacteria which may be found in the intestine? An answer 

 to this question was sought. A specimen taken on July 1st was inactive 

 toward the eight species of bacteria routinely employed, and it was tested 

 against a different series of bacteria, selected at random. The filtrate 

 showed a high activity for an organism of the Salmonella (hog cholera) 



January 15 . . 

 February 1 . . 

 February 15 . 



March 1 



March 15 



April 1 



April 15 



May 1 



May 15 



June 1 



June 15 



July 1 



July 15 



August 1 . . . . 

 August 15 . . . 

 September 1 . 

 September 15 

 October 1 . . . 

 October 15 . . 

 November 1 . 

 November 15 

 December 1 . 

 December 15 



VIRULENCE OF THE INTESTINAL BACTERIOPHAGE FOR 







+ 





 



+ 

 + 

 +++ 

 + 

 + 







+ 







+++ 



+ 

 +++ 

 +++ 



+ 



+ 



+ 



+ 



+ 







+ 



. dysenteriae 





 

 

 

 

 

 

 

 

 

 

 

 



+ 

 ■++ 







■++ 







■++ 





 

 

 





 

 

 

 

 

 

 

 

 



++ 





 

 

 

 

 

 



++ 





 

 

 





 

 

 

 

 

 

 

 

 



+++ 





 

 

 

 

 

 

 

 

 

 

 





 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 



++ 





 





 

 



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++ 





 

 

 

 

 

 

 

 



+++ 





 

 

 

 



Other organisms 



Salmonella + + + 



B. enteritidis + + 



group. When the same experimental tests were repeated on December 

 1st this filtrate was active for B. enteritidis. 



The results of all of these tests are given in table 55. 



From these determinations I reached the conclusion that in those 

 cases where the bacteriophage can not be demonstrated the failure is 

 due solely to the fact that the method employed is defective. This de- 

 fect in the method is due primarily to the fact that B. coli is a hetero- 

 geneous species, hence the inactivity of a filtrate for a strain of this 



