POLYMASTIGINA 309 



him. This flagellate is widely distributed and of common occurrence, 

 especially in tropical and subtropical regions. 



T. elongata Steinberg {T. buccalis Goodey). Similar to T. hominis; 

 commensal in tartar and gum of human mouth. Dobell (1939) con- 

 siders that its name should be T. tenax (O. F. Miiller). 



T. vaginalis Donne (Fig. 145). Similar to the above-mentioned two 

 species; pyriform or fusiform; lO-SOju by 10-20/x; cytoplasm contains 

 many granules and bacteria; commensal in human vagina. Hogue 

 (1943) noticed that this flagellate produces a substance which in- 

 jures the tissue-culture cells. Feo (1944) reported that urethral speci- 

 mens of 144 out of 926 men were found microscopically to contain 



Fig. 145. Trichomonas vaginalis, X1150 (Kudo). 1, a living tro- 

 phozoite; 2, a degenerating amoeboid trophozoite in life; 3, 4, stained 

 trophozoites. 



this flagellate. Some investigators consider the organism as a cause 

 of vaginitis. 



Because of the morphological similarity of these three species of 

 human Trichomonas, a number of workers maintain that they may 

 be one and the same species. Stabler and his co-workers (1941, 1942) 

 obtained negative results by inoculating volunteer human subjects 

 intravaginally with the cultures of T. hominis and T. elongata. On 

 the other hand, Wenrich (1944) considers that there exist distinctly 

 recognizable morphological difl*erences among the three species. 

 Dobell inoculated a rich culture of Trichomonas obtained from his 

 stools into the vagina of a monkey {Macacus rhesus) and obtained 

 a positive infection which was easily proven by culture, but unsat- 

 isfactorily by microscopical examination of smears. The infection 

 thus produced, lasted over three years and did not bring about any 

 ill effect on the monkey. He considers that T. vaginalis and T. 

 hominis are synonyms and that there occur diverse strains different 

 in minor morphological characters and physiological properties. 



T. macacovaginae Hegner and Ratcliffe. In the vagina of Macacus 



