TRICHOMONAS 



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The only difficulty is with the type T. vaginalis. Does it 

 possess three anterior flagella or four ? If the latter, then the genus 

 Trichomonas has as a synonym Tetratrichomonas, and a new name 

 must be found for the forms with three anterior flagella. 



Type Species. — Trichomonas vaginalis Donne, 1837. 



Morphology.— The essential points in the general morphology are 

 the pear-shaped body, the small anterior and ventrally situate cyto- 

 stome without siderophilous lips, and the three anteriorly springing 

 flagella arising (according to Wenyon) from the anterior of the two 

 granules into which the blepharoplast is divided. From the pos- 

 terior granule arises a posterior flagellum, which, passing backwards, 

 forms the undulating membrane and finally terminates in a free 

 posterior portion. From the same granule arises another stiff rod- 

 like structure, the parabasal, which serves as a support for the un- 

 dulating membrane, and often there is a row of granules lying parallel 

 to this rod. Springing from the blepharoplast and directed pos- 

 teriorly over the nucleus is a peculiar body, clear, with bounding 

 lines, which projects from the posterior end as a spine and often 

 contains chromatinic granules. Th's organella is the axostyle, called 

 also the baguette interne. It may be a supporting structure, but 

 it may also be concerned in movement. It does not stain with 

 nuclear stains, and therefore appears clear, while in the living 

 organism it is a refractile rod. 



The nucleus is usually more or less oval, and possesses a membrane, 

 inside which the chromatin is distributed in the form of granules. 



Two chromatinic granules (axoplasts) are often found where the 

 axostyle leaves the cytoplasm. 



Life-History. — Binary division with its nuclear changes have been 

 carefully studied by Kofoid and Swezy . Multiple fission has also been 

 described. Transference from host to host is by the typical cysts. 



Classification. — very large and increasing number of species 

 of doubtful value are in existence — e.g., T . bactrachorum Perty, 1852, 

 in frogs; T. suis Gruby and Delafond, in pigs; T. limacis Dujardin, 

 in snails; T. lacertce Blochmann, in lizards; T. cavicB Davaine, in 

 guinea-pigs; T. perronciti Castellani, 1907, in monkeys; T. colum- 

 barum, in pigeons. Plimmer and others have also recorded a 

 Tetratrichomonas in the blood of snakes (Fig. 79), and this probabty 

 came as an infection from the alimentary canal. Martin and 

 Robertson have also described forms in fowls, and Kuczynski has 

 contributed an elaborate paper on the morphology of the genus. 



Four spscies are said to occur in man — T. vaginalis, T. hominis, 

 T. dysentericB, and T . pulmonalis . 



While some differences do exist in the animal forms, still there is 

 nothing of a specific nature to be found in the human and it is 

 quite possible that they are all one species, and that they are the 

 same as that found in the rat — viz., T . intestinalis, with three anterior 

 flagella, unless, indeed, T. vaginalis really possesses four flagella, 

 but on this point we are not certain; moreover, Kiinstler Was often 

 wrong with regard to the number of flagella {vide Polymastix melo- 



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