440 BACTERIOLOGY. 



BACILLUS DYSENTERIC. 



Another important member of the typhoid-colon 

 group of bacilli is the so-called bacillus dysenteriae. It 

 should not be inferred from this designation that there 

 is known or thought to be a specific bacillus accountable 

 for all the various clinical and pathological manifesta- 

 tions to which the name dysentery is given. The use 

 of the term " bacillus dysenterise " is at present restricted 

 to an organism that is found with such regularity in 

 association with a certain type of the malady that it can 

 reasonably be regarded as etiologically related to it. 



The evidence presented by Shiga, who discovered this 

 organism in 1898 in Japan, and the subsequent observa- 

 tions of Flexner upon dysentery in the Philippine Is- 

 lands, leaves little room for doubt that, in so far as acute 

 epidemic dysentery is concerned, the organism under 

 consideration may reasonably be regarded as the causa- 

 tive factor. By both Shiga and Flexner the organism 

 was almost uniformly encountered in the intestinal con- 

 tents, the intestinal walls, and the mesenteric glands 

 during the acute stages of the disease. Later it was 

 frequently missed, and this became more common as the 

 malady progressed to chronicity or recovery. 



It is a bacillus of medium size, with rounded ends. 

 In general its morphology may properly be likened to 

 that of either the typhoid or colon bacillus. 



It is motile and does not form spores. 



It can be stained with any of the ordinary aniline 

 dyes. It is decolorized by the method of Gram. It 

 may be cultivated on all the ordinary media. It grows 

 at room-temperature, but better at the temparature of 

 the body. It does not liquefy gelatin. 



