HOST-PARASITE RELATIONS AMONG TRICHOMONADS 155 



ads found in man, the common Trichomonas of the monkey, 

 Brumpt (igogb), Prowazek (1912), Kessel (19280?), and of the 

 domestic pig, Kessel (1928a), Pentatrichomonas (Wenrich and 

 Yanoff, 1927) of the white rat, and the Trichomonas reported 

 from kittens by da Cuhna and Muniz (1922), Brumpt (1925), 

 Tanabe (1926), and Kessel (1926 and 1928c), and by Brumpt 

 (1925) from the dog. This type has not been known to produce 

 cysts. It may be designated as the human Trichomonas type. 



INFECTION EXPERIMENTS 



Attempts to infect lower mammals with Trichomonas of man 

 have met with varying degrees of success, some workers recording 

 positive results, and some negative. The positive reports of some 

 of the earlier investigators were made without their being certain 

 that the experimental animals with which they worked were 

 actually negative for Trichomonas prior to the experiment. Con- 

 sequently the negative results of Pringault (1920) in attempting 

 to infect the rat, the rabbit, the guinea-pig, and the cat, and of 

 Hogue (1922) to infect cats and rabbits were emphasized by Heg- 

 ner ( 1927c) in his conclusion that "the host-parasite specificity of 

 the human intestinal Trichomonas seems quite rigid." 



It seems altogether probable that Hegner (1927c) was influenced 

 in this conclusion concerning the rigidity of Trichomonas by his 

 experiments with Giardia-, most of his transmission experiments 

 with Giardia having yielded negative results. He accordingly dis- 

 missed as valueless the earlier reports of positive transmission of 

 Trichomonas and failed to attach significance in this relation to 

 the work of Kessel (1926), in which kittens were experimentally 

 infected with Trichomonas from man, Macaciis monkeys, the white 

 rat and the domestic pig, and also the work of Wenrich and YanofT 

 1927), who infected the white rat with Pentatrichomonas of man. 

 Knowles (1926) also reported infecting kittens with Pentatrichom- 

 onas of man. 



As a result of the findings just mentioned, Kessel (1928c) con- 

 cluded that Trichomonas felis da Cunha and Muniz (1922) was in 

 all probability not a species of Trichomonas peculiar to the cat, but 

 that Trichomonas infections in kittens might be acquired from a 

 variety of different animals. He further stated that Trichomonas 

 appears to be a parasite which is not restricted to a given host, 

 but is one which will live equally well in several hosts. By analogy 



