BACTERIA SUSCEPTIBLE TO BACTERIOPHAGY 243 



Races of the bacteriophage virulent for B. dysenteriae Shiga have been 

 isolated up to the present from a variety of sources, including the stools 

 of convalescents from bacillary dysentery (d'Herelle^^*^); the stools of 

 individuals effected with mild intestinal disturbances (d'Herelle^^^) ; 

 the feces of normal men (d'Herelle^^-), particularly in epidemic periods 

 (d'Herelle'^^'O ; the feces of domestic animals (d'Herelle^^ ') ; from drinking 

 water and from rivers (Dumas^*^); from cultivated soil (Dumas^^^); 

 from sea water at the mouths of rivers; and from tap-water (d'Herelle^^i)^ 

 In brief, races of bacteriophage virulent for B. dysenteriae may be en- 

 countered in everything that is exposed to contamination by excreta. 



2. B. dysenteriae Hiss (Eherthella paradysenteriae) 



Everything that has been said in this text upon the subject of bac- 

 teriophagy with the Shiga dysentery bacillus and of the behavior of this 

 organism toward the bacteriophage may be applied without change to 

 B. dysenteriae Hiss. 



We have seen that a bacteriophage virulent for B. dysenteriae Shiga 

 is also virulent for the bacillus of Hiss. As a general rule the virulence 

 for a bacterium of any kind within the colon-typhoid-dysentery group 

 frequently extends to the Hiss bacillus. 



Reichert^^" has observed an incompatability between the virulence 

 of a bacteriophage for B. coli and for B. dysenteriae Hiss. He has 

 found that if, by passages, a bacteriophage acquires a virulence for the 

 first it loses virulence for the second, and the reverse is likewise true. 

 According to my own observations the situation described by Reichert 

 is a fortuitous coincidence rather than a general law for I have often 

 encountered the simultaneous existence of these two virulences. In 

 this connection I have even effected the following experiment. After 

 preparing a mixed suspension by adding to bouillon a drop of a very 

 concentrated suspension of B. coli, one demonstrated to be susceptible, 

 and then one drop of a very heavy suspension of B. dysenteriae Hiss, 

 a strain also susceptible, complete bacteriophagy in about 12 hours 

 occurred through the action of a bacteriophage isolated from a dysentery 

 convalescent. 



Beckerich and Hauduroy^^ have found that a bacteriophage virulent 

 for the enterococcus (isolated by them from the feces of a horse) was 

 likewise virulent for B. coli and for B. dysenteriae Hiss. 



Secondary cultures reinoculated into litmus sugar media do not fer- 

 ment the sugars in the same way as do normal bacilli. Media contain- 

 ing glucose, maltose, and mannite become acid after ten days; those 



