172 INFECTIONS OF THE DIGESTIVE TRACT 



siderations regarding the influence of the number of the 

 bacilli and the vigor of the defenses doubtless apply also 

 to the case of infections with the typhoid bacilli, but here 

 there is probably never any primary intoxication from 

 the presence of toxins in food, for the reason that the 

 typhoid bacilli, requiring such special conditions for 

 multiplication, do not often find the requisite condi- 

 tions for giving off their poisons except within the human 

 body. 



Dysentery Bacilli. Very few years have passed since 

 it became apparent that certain microorganisms which 

 had previously been regarded as colon bacilli are in 

 reality quite distinct from them and stand in a direct 

 causative relation to the widespread intestinal disorders 

 of temperate climates which are grouped under the 

 term dysentery. Takati Shiga, a gifted young Japanese 

 with a German training, was able to show that the in- 

 testine in dysentery contains large numbers of bacilli 

 which, while resembling colon bacilli in some respects, 

 yet differ from them in their fate, in their appearance 

 on agar plates, in their lack of motility, in their failure 

 to make acid from sugar media, in their failure to pro- 

 duce indol or make gas, in their power to set up in man 

 a disease clinically like dysentery, and in their ability 

 to confer on the human blood serum the property of 

 specific agglutination in high degree. This discovery 

 was soon followed by the researches of Flexner in Manila, 

 which showed that there is another type of dysentery 

 inciter allied to the Shiga bacillus but differing from 

 it in the direction of retaining more fully some of the 



