THE DYSENTERY GROUP 217 



blood in the stools. Within recent times two distinct forms have 

 been distinguished : one variety, amebic dysentery, is caused by a 

 protozoon ; the other form, badllary dysentery, is caused by bacilli 

 of the colon-typhoid group. 



In 1898 Shiga, a Japanese bacteriologist, isolated an organism 

 from the stools of dysentery patients which he found would agglu- 

 tinate with the serum of those patients and not with that of normal 

 individuals. Moreover, he was not able to find the organism in the 

 feces of patients suffering from other diseases nor in those of normal 

 individuals. Shiga's bacillus is now considered the causal agent 

 of the majority of acute dysentery epidemics which occur in tem- 

 perate climates. 



In 1899 Flexner, while investigating dysentery in Manila, isolated 

 a bacillus from dysenteric stools which at that time he considered 

 identical with that isolated by Shiga, but later found that it dif- 

 fered in agglutinative reactions. In the same year Kruse in Ger- 

 many isolated similar bacilli from cases of dysentery. In 1902 

 Park and Dunham obtained an organism from a severe case of 

 dysentery at Seal Harbor, Mt. Desert, Maine, which proved by 

 its different agglutinating characteristics to be still another strain. 

 Since that time several others have been described. One writer 

 has even described fifteen different forms which have fermentative 

 characteristics distinguishing them one from the other. The 

 following classification of Hiss, in which all members fall into one 

 of four groups, is the generally accepted one : 



Type 1. Shiga. Ferments dextrose. 

 Type 2. Park-Hiss. Ferments dextrose and mannite. 

 Type 3. Flexner-Strong. Ferments dextrose, mannite, and saccharose. 

 Type 4. Harris-Wollstein. Ferments dextrose, mannite, saccharose, and 

 maltose. 



Of the four types it is generally agreed that Type 1 appears most 

 frequently in the severest forms of the disease ; types 3 and 4 are 

 found more frequently than the others in the dysentery or summer 

 diarrhea of young children. 



Morphology and Staining. The organisms closely resemble 

 the typhoid bacilli save that they are somewhat thicker, and 



