VIRULENCE OF THE BACTEEIOPHAGE 111 



will return to a consideration of this bacteriophage later, in the 

 chapter dealing with barbone (hemorrhagic septicemia of the 

 buffalo) . 



When isolated from the body all the strains presented an average 

 or feeble virulence toward the different intestinal bacteria. After 

 about a dozen passages at the expense of the bacterium of bar- 

 bone these accessory virulences became markedly attenuated. 



B. pestis 



Twelve strains of bacteriophage active for B. pestis have been 

 isolated. Eleven of these were secured from the excreta of rats 

 in the different villages of Indo-China where plague was epidemic. 

 The twelfth was derived from the feces of a patient convalescent 

 from plague. This is the only strain which has been maintained. 

 This strain was also active for the bacillus of pseudotuberculosis 

 of guinea pigs. 



Bacillus of flacherie 



The bacillus in question was isolated from the bodies of silk- 

 worms which had died of a disease presenting the characteristics 

 of flacherie in the breeding establishments in Indo-China. The 

 bacteriophage is frequent in the intestine of the healthy worms 

 among a contaminated stock. The activity of this bacteriophage 

 was the same for each of the three strains of the bacillus tested, 

 isolated from three different breeding places. 



B. subtilis 



One strain of bacteriophage active for this bacillus was secured 

 in the stools of a patient with dysentery. Having but rarely 

 tested the virulence of the bacteriophage toward B. subtilis it is 

 impossible to say if this virulence is frequent or exceptional. 



Vibrio cholerae 



Among about one hundred cases of cholera studied in Indo- 

 China it was possible to observe but one following recovery. In 

 this last, in spite of daily examination of stools, in but a single 

 specimen taken at the beginning of convalescence has a bacterio- 



