

PATHOGENIC BACTERIA. 157 



and then through bites and scratches affect man and other ani- 

 mals. Clothing, vomit, and the excretions generally, likewise, 

 act as carriers of the infection. In man three forms of the dis- 

 ease are recognized according to the mode of infection and 

 course of the disease viz., bubonic, pulmonic, septicemic. 



Bacillus Dysenteriae. (Shiga, 1898.) 



The term dysentery is applied to an intestinal disease dis- 

 playing more or less 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 

 amoeba, while non-amoebic forms can probably be produced by 

 several bacteria. Chief among these is the bacillus first de- 

 scribed by Shiga in Japan, and since then found by Kruse in 

 Germany, by Flexner, Strong, and Harvie in the Philippine 

 Islands, and by Vedder and Duval in the United States. 

 Although it is not absolutely proved that it is the cause of the 

 disease, still the fact that it is constantly present in the faeces in 

 one type of dysentery, that such cases give a positive agglu- 

 tination reaction, the production of a curative serum by the 

 immunization of animals with pure cultures, and the results 

 on experiment animals, leave little doubt as to the specificity 

 of the organism. 



Origin. The dejecta of dysenteric patients. 



Form. A plump bacillus with rounded ends, resembling the 

 typhoid and colon bacilli. 



Properties. Motility doubtful, but numerous flagella have 

 been demonstrated. Does not form spores. 



Staining. Stains readily, negative to Gram, facultative an- 

 aerobe. 



Growth. Best at 37 C. Killed by ten minutes' exposure to 

 55 C. 



Gelatine. A white line of growth along puncture; super- 

 ficial growth slight. 



Bouillon. Uniform clouding. Indol usually not produced; 

 milk not coagulated. 



Agar. Resembles typhoid bacillus. 



Potato. Thin whitish layer, turning light brown. 



No gas-formation in glucose or lactose media. 



