192 



THE BACTERIOPHAGE 



1. Marie Mo. . . . (fifty-five years, fig. 6). 



2. Louis Pi. ... (seventeen years, fig. 7). 



3. Franc. ois Jod. . . . (thirty-four years, fig. 8). 



In these cases the virulence of the intestinal bacteriophage 

 was determined for B. coli, B. typhosus, B. paratyphosus A and 

 B t and B. dysenteriae Shiga. It is needless to comment on these 

 observations, since examination of the curves is more instructive 

 than would be an explanation. 



Day of the Disease 



O' 



>>.2 

 ^5 



'58 



< 



FIG. 8. FRANCOIS JOD (34 years) CLINICALLY, TYPHOID FEVER 



Virulence for 



B. typhosus 

 coli. . 



B. paratyphosus A - 

 B, paratyphosus B - 

 B. dysenteriae Shiga 



What is the causative bacillus in each of these three cases? 

 It is indeed difficult to make a diagnosis by means of the bacterio- 

 phage, which as we have seen, but rarely develops a single 

 virulence. 



This virulence extends to other bacteria of the same group to 

 a more or less marked degree, and this fact is particularly in 

 evidence when working with the representatives of the colon- 

 typhoid-paratyphoid-dysentery group. It appears, however, in 

 the case of Louis Pi. ... that the causative bacillus must have 

 been the typhoid bacillus, with Marie Mo. . . . B. paratyphosus A, 

 and in Frangois Jod. . . . B. paratyphosus B. 



