254 THE BACTERIOPHAGE AND ITS BEHAVIOR 



warranted. As a matter of fact we are only at the beginning of this 

 phase of the subject. 



3. B. paratyphosus B (Salmonella Schottmillleri) 



But few studies have been made of this organism with regard to its 

 behavior toward the bacteriophage, but it would appear that it is 

 somewhat less heterogeneous than is B. typhosus, for the races of the 

 bacteriophage which I have isolated haVe been, in general, virulent for 

 all of the strains with which I have tested them. 



A bacteriophage virulent for B. paratyphosus B is frequently found 

 in the intestinal tracts of man and animals, a virulence for this bacillus 

 being extremely common, being exceeded in frequency only by that for 

 B. dysenteriae (d'Herelle^'^). 



Upon a few occasions I have obtained resistant colonies assuming the 

 viscous and flowing form of the bacillus of Friedlander, 



Jf.. B. suipestifer (Salmonella suipestifer) 



I have isolated a bacteriophage virulent for this bacillus from the 

 stools of a normal man. With a moderate virulence for a strain of 

 B. suipestifer it was without virulence for organisms of the colon- 

 typhoid-dysentery group. I have also isolated bacteriophages virulent 

 for B. suipestifer from the intestinal contents of normal horses, but 

 these races have shown an accessory virulence for B. dysentenae.^^^-^'^^ 



5. B. enteritidis (Salmonella enteritidis) 



Upon several occasions I have found bacteriophages virulent for 

 either B. typhosus or the paratyphoids A or B, to be virulent for certain 

 strains of B. enteritidis also. Frequently I have isolated such races 

 from the excreta of animals. •^^■' 



6. B. typhi murium (Salmonella typhi-murium) 



Races of the bacteriophage virulent for B. paratyphosus B occasionally 

 possess some degree of virulence for this bacillus. I have isolated 

 very active strains from the intestinal tracts of white and gray rats 

 which were resistant to the experimental disease caused by the ingestion 

 of cultures of B. typhi murium. 



Certain resistant colonies are composed of bacilli which are very viru- 

 lent and they may be, under certain circumstances, utilized for the 

 destruction of gray rats, which, as a rule, resist the ingestion of the 



