22, i Sellards and Leiva: Amoebic Dysentery 5 



the purpose of obtaining general orientation. Obviously, the 

 results cannot be applied directly to Entamoeba histolytica any 

 more than the effects of experiments on lower animals can be 

 applied directly to man. It is also perfectly clear that the 

 effects in vitro do not imply a corresponding action in the 

 animal body. 



Vedder, as the result of his work with emetine on Umax 

 amoebae, suggested that this drug in solution in the body fluids 

 might be capable of killing or inhibiting Entamoeba histolytica 

 in the tissues of the intestinal mucosa, or even in the liver. 

 Subsequent experience has amply justified this suggestion. In 

 contrast to this, the entirely insignificant action obtained in 

 vitro with Tinospora rumphii offers no encouragement for its 

 use in amoebic infections. 



II. RESULTS OBTAINED IN TREATING CATS INFECTED WITH 

 ENTAMCEBA HYSTOLYTICA 

 Literature.— The treatment of amoebic dysentery in lower 

 animals WHS undertaken with the purpose of developing a 

 dependable method for the experimental chemotherapy of this 

 disease. The infection of laboratory animals with Entamoeba 

 histolytica cannot be accomplished with ease and precision. 

 Cats are ordinarily used, and the course of the experimental 

 disease is best understood in the cat. Adult cats are not very 

 susceptible to infection, and in kittens the disease usually assumes 

 a fulminating type which obviously presents enormous diffi- 

 culties in experimental therapy. This is well illustrated by the 

 experience of previous workers. Dale and Dobell became dis- 

 couraged in view of their failure to modify fulminating infec- 

 tions in kittens by treatment with emetine. They concluded 

 that emetine has no direct action on Entamoeba histolytica, either 

 in man or in kittens; its undoubted therapeutic effect in man was 

 ascribed, not to any direct action on amcebse, but to some 

 occult alteration of the tissues of the host through which the 

 tissues become more resistant to amoebae. This alteration of 

 the tissues was supposed to be produced by emetine in man, but 

 not in cats. 



Dale and Dobell worked exclusively with small kittens, six to 

 eight weeks old, weighing 500 to 600 grams. Emetine failed 

 to cure infected kittens and also failed, prophylactically, to 

 prevent infection when administered before the injection of 

 amoebae. It was given hypodermically, by rectal injection, and 

 by mouth as the double iodide with bismuth. It is much to be 



