TYPES OF DYSENTERY 131 



pation of the Phillipine Islands was accompanied by a frightful 

 epidemic of dysentery among the American soldiers, and until 

 the city of Manila was cleaned up it was a veritable pest hole for 

 the disease. 



There are many different types of dysentery, especially in the 

 tropics, each showing somewhat different symptoms and having 

 to be treated in different ways. Some cases of dysentery are 

 due merely to improper diet, some to disturbances of the digestive 

 tract due to other diseases, and the majority to intestinal para- 

 sites of some kind, either bacteria, protozoans, or worms. In a 

 restricted sense the term " dysentery " is used for intestinal dis- 

 eases caused either by bacteria or protozoans. The diseases 

 caused by protozoans other than amebse are discussed in the 

 chapter preceding this. " Bacillary Dysentery " is a bacterial 

 disease and need not be discussed here except in comparison with 

 the other types of dysentery. It occurs in temperate as well as in 

 tropical countries and is very common in epidemic form in armies, 

 prisons and asylums. Amebic dysentery, on the other hand, 

 is uncommon outside of warm climates but is endemic in local 

 areas in almost all tropical and subtropical countries. In some 

 districts 85 per cent of all dysentery is caused by amebse. Amebic 

 dysentery is common on the Gulf Coast of the United States, 

 and endemic cases probably occur throughout the United States, 

 since numbers of cases are on record from such northern states 

 as Minnesota and Iowa, though apparently not introduced directly 

 or indirectly from more southern localities. Since the beginning 

 of the European war amebic dysentery has become fairly common 

 in France. The so-called " trench diarrhea " is often amebic 

 dysentery. Unlike the bacterial disease it does not give rise to 

 extensive epidemics in places where it is not normally found. 



The r61e played by amebse in dysentery was in doubt for a 

 long time. The presence of amebse in perfectly healthy indivi- 

 duals, and the fact that amebse grown in artificial cultures would 

 never cause dysentery experimentally, confused the problem. 

 As said before there are species of ameba, especially Endammha 

 coli, which, though closely resembling the real villain, E. histo- 

 lytica, live in the human intestine apparently without doing the 

 slightest damage. Neither E. coli nor E. histolytica will grow 

 on cultures, the cultured amebse being distinct from either, and 

 quite incapable of damaging the intestine. Walker and .Sellards 



