648 FAMILY: TEICHOMONADIDiE 



as modified Trichomonas, is an exceedingly difficult one, and no definite 

 decision can be reached unless it is clearly established that the characters 



are constant. 



Oenus : Trichomonas Donne, 1837. 



The flagellates of this genus have more or less pear-shaped bodies, 

 three to five anterior flagella, and a recurrent axoneme, which is attached 

 to the border of an undulating membrane. The axoneme may or may 

 not be continued beyond the membrane as a posterior flagellum. There 

 is a definite cytostome near the base of the flagella. An axostyle is present, 

 and also a fibre which runs along the line of attachment of the undulating 

 membrane. A nucleus is situated at the anterior end of the body, and 

 anterior to it is a group of blepharoplasts, from which the flagella and 

 other structures arise. In some forms a parabasal has been described in 

 the cytoplasm between the nucleus and basal fibre of the undulating 

 membrane. Reproduction is by binary fission, and encystment also 



occurs. 



TRICHOMONAS IN MAN. 



There is a large number of species of this genus, which differ from one 

 another in size, shape of the body, and the number of flagella. It appears 

 that at least three occur in man : T. hominis of the intestine, T. elongata 

 of the mouth, and T. vaginalis of the vagina. It cannot, however, be 

 considered as definitely established that these are distinct species. 



Trichomonas hominis (Davaine, 1860). — This common intestinal flagel- 

 late of man was first recorded by Davaine in 1854 as Cercomonas. In 1860 

 he gave a figure and more detailed description of the organism under the 

 name Cercomonas Jioininis. It was later placed in Donne's genus, Tricho- 

 monas, by Leuckart (1879) and others, and is now generally known as 

 T. hominis. As noted above (p. 621), Moquin-Tandon in the year 1860 

 had already proposed the name C. obliqua for a flagellate usually regarded 

 as a Trichomonas, so that, according to rule, the name should be T. obliqua 

 if there is no doubt as to the identity of the organism named by him. 

 Grassi (1879a, 1881a) referred to it as Monocercomonas hominis. On 

 account of these difficulties of nomenclature. Stiles (1902) proposed the 

 new name Trichomonas confusa. 



T. hominis is probably the commonest intestinal flagellate of man 

 (Fig. 266). As a rule, it is only seen in diarrhoeic stools, but that it is 

 still present when the stools are formed can be demonstrated by adminis- 

 tering saline purges, or by the inoculation of faeces into certain media, as, 

 for instance, Hogue's egg medium, and incubating at 24° C. for a few days, 

 as advocated by Hegner and Becker (1922) and Reichenow (1923). Its 

 occurrence in diarrhoea, however, is due most probably to the fact that it 

 is only when the stools are liquid that the flagellate in its active condition 



