PATHOGENIC BACTERIA 179 



danger. Direct infection by dust or other material seldom 

 occurs. 



Products. A toxin has been obtained and immunity has been 

 effected; the serum of immune animals has protective prop- 

 erties. The serum likewise shows agglutinating powers, as 

 with typhoid and cholera serums. 



Habitat. Not found in water, but most likely spreads from 

 the soil in damp and darkened areas. Rats become affected 

 first, and then through fleas affect man and other animals. 

 In man three forms of the disease are recognized according to 

 the mode of infection and course of the disease viz., bubonic, 

 pulmonic, septicemic. 



Vaccines. The vaccines of Haffkine and Terni and Bandi 

 have been used extensively, and with some good results. 



Antitoxins. The antitoxins of Yersin and of Lustig have 

 been used, but without much result. 



Bacillus Dysenteriae (Shiga, 18p8). The term dysentery 

 is applied to an intestinal disease displaying more or less con- 

 stancy 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 those is the bacillus first described 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 feces in one type of dysentery, that such cases 

 give a positive agglutination 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. 



