THE COLON-TYPHOID GROUP 145 



Staining. Gram positive, easily stained with ordinary 

 dyes. 



Growth. Strictly anaerobic. Forms abundant gas in glu- 

 cose, gelatin, and liquefies cultures, producing butyric acid 

 odor. Best temperature between 20 and 30 C. 



Patho genesis. Produces a powerful toxin in the tissues, 

 like the tetanus bacillus. This toxin may be present in the 

 affected meat without causing decomposition, and thus give 

 rise to poisoning. 



Bacillus Dysenteriae (Shiga, 1898). The term dysen- 

 tery is applied to an intestinal disease displaying more or less 



Fig. 63. Bacillus dysenteriae from agar culture. Fuchsin stain. Zett- 

 now prep. (Kolle and Wassermann). 



constancy in its clinical manifestations, but having, as is now 

 known, a variety of causative agents. It is fairly certain that 

 one type is the result of infection with an ameba, while non- 

 amebic forms can probably be produced by several bacteria. 

 Chief among these is the bacillus first described by Shiga in 

 Japan, and since then found by Kruse in Germany, by Flex- 

 ner, Strong, and Harvie in the Philippine Islands, and by 

 Vedder and Duval in the United States. The fact that it is 

 constantly present in the feces in one type of dysentery, that 



