. Animal parasites and human disease. Insect Vectors; Parasites; Parasitic Diseases; Medical parasitology; Insects as carriers of disease. 120 INTESTINAL FLAGELLATES AND CILIATES instead of three have been described but they are not so common and there seems to be room for doubt as to whether these may not be abnormal forms or division stages of the one species. Goodey describes the mouth form of the parasite as having four flagella. Trichomonas swims by active lashing movements of the free flagella and by wave motions of the undulating membrane. The body revolves as the animal wends its way t
. Animal parasites and human disease. Insect Vectors; Parasites; Parasitic Diseases; Medical parasitology; Insects as carriers of disease. 120 INTESTINAL FLAGELLATES AND CILIATES instead of three have been described but they are not so common and there seems to be room for doubt as to whether these may not be abnormal forms or division stages of the one species. Goodey describes the mouth form of the parasite as having four flagella. Trichomonas swims by active lashing movements of the free flagella and by wave motions of the undulating membrane. The body revolves as the animal wends its way through the semi-liquid substances in which it lives. Multiplication is by longitudinal division of the body, the flagella and undulating membranes and internal structures all being duplicated before the animal splits into two. A process of multiple fission resulting in the formation of eight individuals has also been described. Encystment, such as occurs in other intestinal protozoans, has definitely been observed only recently in Trichomonas. Some of the flagellates, after escaping from the body with the faeces, soon degenerate, gradually losing all their appendages except the undulating membrane. With- out their flagella, and with their ameboid movements, these animals closely resemble amebae but can usually be identified by the undulating movement which persists at one side of the body. Others, without losing infelunall)' ATpvtZcyst- their appendages, become round and mo- ment stage; B, encysted tionless as if in a cyst, but with no cyst Lynch.) > er wa^ around them. When warmed up they stretch themselves out and resume an active life. It is probable that these forms are preparing for encystment, since they correspond with pre-encystment forms (Fig. 31 A) recently described by Lynch. Lynch, who found con- siderable numbers of cysts in a heavily infected case in South Carolina, describes the cysts (Fig. 31B) as thin-shelled, pear- shaped bodies, about three-fourths the siz
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectparasites, bookyear19
