30 RESEARCH IN PROTOZOOLOGY 



Kessel (i928r) also reports experimental infections of Trichom- 

 onas of man and of Macacus monkeys in kittens. 



Another evidence of close species relationship between E. his- 

 tolytica of man and of monkeys recently presented by Dobell 

 (1928) is that he has found emetine a satisfactory therapeutic 

 measure in amoebic infections in monkeys. 



Hegner and Ratcliffe (1927) gave the name T. macacovagince 

 to a Trichomonas from the vagina of a Macacus monkey. Hegner 

 (1928a) later concluded, however, that the Trichomonas of the 

 intestine and vagina of monkeys are identical so this name will 

 become a synonym either of T. anfJiropopithcci Deschiens, 1927, 

 of T. vaginalis or of T. hominis dependent upon whether Trichom- 

 onas of man and of the lower primates are concluded to be the 

 same species and also as to whether T. hominis and T. vaginalis 

 of man are eventually decided to be a single species. Further inves- 

 tigational work is necessary on this point, although Hegner's find- 

 ings in the monkey lend support in favor of the hypothesis that 

 T. vaginalis and T. hominis of man are identical. 



METHODS AND PROBLEMS 



Investigations with the intestinal protozoa of monkeys involve 

 problems and methods in technique, quite similar to those encoun- 

 tered in studying the human intestinal protozoa, stool examina- 

 tions, administration of purgatives, and cultural methods of the 

 protozoa being the same. 



Monkeys as a rule show a higher incidence of infection with 

 intestinal protozoa than is found in man. This is undoubtedly 

 owing to the unclean habits of the monkeys. Whether monkeys 

 in their natural state in the tropics show a greater tendency to 

 exhibit symptoms of acute amoebic dysentery and amoebic liver 

 abscess than they do in captivity in more temperate regions is a 

 problem of considerable interest, by way of comparison with 

 human amoebiasis, since more cases of acute amoebiasis in man 

 are found in tropical than in temperate regions. 



In addition to monkeys being used as experimental animals in 

 the solution of human amoebiasis problems they may also be of 

 service in animal cross-infection work with lower mammals, since 

 man ordinarily cannot cooperate in such experiments. Walker 

 (1913) transferred Balantidium coli from the domestic pig to mon- 

 keys, and Brumpt (1909) infected the pig with B. coli of the 



