6 ANIMAL PAEASITES. 



body has expelled, or is in the course of expelling as foreign to 

 it, they are properly only to be regarded as indirectly parasitic 

 upon the human body. We shall, therefore, refer to them super- 

 ficially here, and only devote a closer attention to two species. 

 How widely diffused they are in the body is shown by the fact 

 that Ficinus, for example, found sluggish, bean-shaped Infusoria, 

 ~ m ^ inch, and sometimes double this size, of a globular form, 

 in the perspiration of the feet, on the places where the epidermis 

 separated in caseous crumbs, as well as in the moist walls of the 

 folds of skin in little children^ and that others have met with 

 them in purulent and foul secretions from the vagina, urethra, 

 and bladder, putrescible urine, &c. 



1. Trichomonas vaginalis. (PI. I, fig. 2.) 



Diesing has placed this animalcule in his Subclassis I, Achae- 

 thelmintha ; Sectio 1, Ach. mollia ; Ordo I, Prothelmintha ; Sub- 

 ordo, Aprocta ; Nibus, Atricha ; Familia II, Monadineae ; Sub- 

 fam. Ill, Cercomonadinea ; Genus XIV, Trichomonas (Duj.) ; and 

 described it as follows : 



Animalcula solitaria, libera. Corpus nudum, loricd destilutum, 

 subglobosum } brevicaudatum, mollitie sua mutabile, hyalinum, d't- 

 visione spontanea simplici bipartitum v. indivisum. Os (?) obliquo- 

 terminale, limbo ciliatum. Flagellum simplex, terminate. Ocellus 

 nullus. Endoparasita. 



Trichomonas vaginalis : Corpus nodulosum (gelatinosum) lac- 

 teum ; cauda brevis ; flagellum corpore triplo longius. Motus 

 vacillans. Longit. ^.'" (Duj., ' Hist. Nat. Inf./ 300 tab., iv, 

 fig. 13.) 



Notwithstanding that Dujardin, who also describes a Tricho- 

 monas in the intestine of Limax agrestis, recognised the animal 

 nature of this structure, it has hitherto been unable in Germany 

 to establish its title to a place amongst the true independent 

 parasites of man. Some regarded this parasite as ciliated 

 epithelium (compare Ecker's figure of the ciliated epithelium of 

 the auditory organ of Petromyzon marinus, in Muller's ' Archiv/ 

 1844, Taf. xvi, figs. 1, 2). Others considered the animal as a 

 mite. Recently, however, Kolliker and Scanzoni (see Scanzonr's 

 ' Beitrage zur Geburtskunde/ &c., Band ii) have confirmed 

 Donne's statements (' Rech. microsc. sur la nature du Mucus/ 

 Paris, 1837; and ' Cours de Microscopic/ Paris, 1845, pp. 157 



