TREATMENT OF AMEBIC DYSENTERY 137 



the amebae to the tissue underlying the mucous membrane, and 

 here they make extensive excavations. The lesions are most 

 common in the upper half of the large intestine but can be found 

 from the lower part of the small intestine to the rectum. The 

 exposed ulcerations vary from the size of a pinhead to that of a 

 silver dollar, their ragged edges tending to roll into the crater- 

 like areas. Often the tunnel-like excavations under the mucous 

 membrane connect with one another. 



Liver abscess is a common result of infection with Endamoeba 

 histolytica. Often these abscesses are of large size, filled with a 

 slimy and somewhat bloody chocolate-colored pus. Over a quart 

 of such pus has been removed from an amebic liver abscess. 

 The parasites are found at the edges of the abscess, eroding more 

 tissue and enlarging the pus cavity. How they reach the liver 

 to do their damage is not certainly known, but it seems probable 

 that they bore into blood vessels in the walls of the diseased large 

 intestine and are carried by the portal vein to the liver, where 

 they find a fertile feeding ground. 



Infections with E. histolytica are very persistent, and, with- 

 out treatment, may persist throughout the lifetime of the host. 

 In many cases dysenteric symptoms never develop, while in other 

 cases there may be intermittent attacks or an attack after the 

 infection has persisted harmlessly for months or years. 



Treatment and Prevention. One of the greatest discoveries 

 in the field of medical treatment since the production of salvar- 

 san by Ehrlich is the discovery of emetin as a specific against 

 amebic dysentery. Emetin is an alkaloid prepared from ipecac, 

 the extract of the roots of a Brazilian herb. It was long known 

 that ipecac sometimes had a very marked effect on dysentery, 

 but since amebic dysentery has only recently been differentiated 

 from other forms very variable results were obtained from its use. 

 Ipecac has a decided disadvantage in that it causes violent vom- 

 iting, but its alkaloid, emetin, in the form of emetin hydrochloride, 

 while possessing all the beneficial properties of ipecac, can be used 

 in the form of injections into the veins, and therefore does not 

 cause vomiting. Experiments with cultural species of amebse 

 showed that emetin (emetin hydrochloride) is destructive to 

 amebse when diluted 500,000 times, and the intestinal amebae 

 on a microscope slide become round and motionless and appar- 

 ently dead when subjected to this very dilute solution. It is now 



