702 Dysentery 



The Different Varieties of the Dysentery Bacillus. 



Three varieties of the dysentery bacillus may now be de- 

 scribed : 



1. The Shiga-Kruse variety. 



2. The Flexner variety. 



3. The Hiss-Russell variety. 



The differences by which they are separated are to be 

 found in the agglutinability by artificially prepared immune 

 serum, each of which exerts a far more pronounced effect 

 upon its own variety than upon the others, and in the be- 

 havior toward sugars with reference to acid formation and 

 gas production. It seems not improbable that the future 

 will have much to say about the dysentery bacillus, and 

 that the validity of much that is accepted at present may 

 have to be amended. This seems to be particularly true 

 with regard to the matter of fermentation, the details of 

 which are displayed in the following table taken from Muir 

 and Ritchie's "Manual of Bacteriology." 



Pathogenesis. Shiga and Flexner found that infection 

 of young cats and dogs could be effected by bacilli introduced 

 into the stomach, and that lesions suggestive of human dys- 

 entery were found in the intestines. Kazarinow * found that 

 when guinea-pigs and young rabbits were narcotized with 

 opium, the gastric contents alkalinized with 10 c.c. of a 10 

 per cent. NaOH solution, and a quantity of Shiga bacilli 

 introduced into the stomach with an esophageal bougie, it 

 was possible to bring about diarrhea and death with lesions 

 similar to those described by Vaillard and Dopter. 



In these experiments it was found that rapid passage 

 through animals greatly increased the virulence of the 

 bacilli, and it was also observed that though 0.0005 c.c. of 

 a virulent culture introduced into the peritoneal cavity 

 would cause fatal infection, to produce infection by the 

 mouth as above stated required the entire mass of organisms 

 grown in five whole culture- tubes. 



The virulent organisms are infectious for guinea-pigs and 

 other laboratory animals, and cause fatal generalized infec- 

 tion without intestinal lesions. 



Lesions. The lesions found in human dysentery are 

 usually fairly destructive. They consist of a severe catarrhal 

 and pseudomembranous colitis, which later passes into a 



* " Archiv. f. Hyg.," Bd. L, Heft i, p. 66; see also "Bull, de 1'Inst. 

 Past.," 15 Aout, 1904, p. 634. 



