CHAPTER XXIII. 



The group of bacilli found in cases of epidemic, endemic, and sporadic 

 dysentery The morphological, biological, and pathogenic char, 

 acters of the several members of the group The differentiation 

 of the different types of bacilli. 



BACILLUS DYSENTERIC. 



THE investigations of epidemic dysentery by Shiga, 

 Flexner, Kruse, Vedder, Duval, Basset, Park, and many 

 others, have demonstrated that this disease is caused by 

 an organism that varies somewhat in its characters as 

 encountered in different cases. So far at least four 

 types of organisms have been found that differ in 

 minor particulars, though not sufficiently to warrant 

 their designation as distinct species. The type of 

 'organism first encountered by Shiga, in Japan, is the 

 one that is probably very widely distributed, because it 

 has been found in practically every place where search 

 has been made for it. The type of organism encountered 

 by Flexner in the Philippine Islands, and believed by him 

 to differ from the Shiga type, has also been found very 

 generally in the United States, especially in dysentery 

 occurring in infants. The type of organism isolated by 

 Hiss and Russell, and later by Park and his associates, 

 has most of the characteristics of the Flexner type of 

 organism, though the agglutination reaction shows that 

 it is not identical with it. 



At first the German investigators were inclined to 

 regard the Flexner type of organism as having no 

 causative relation whatever to dysentery, but later de- 



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