[Illustration: FIG. 22.--_Cercomonas hominis_, Dav. From an Echinococcus cyst. (After Lambl.)] The Flagellata observed by Ekeckrantz (1869) in the intestine of man belong to this form--at least to the larger variety--and Tham (1870) reported fresh cases soon after. Lambl’s publication of 1875, which was written in Russian, and became known through Leuckart’s work on parasites, also alludes to apparently typical Cercomonads, which, however, were discovered, not in the intestine, but in an _Echinococcus_ cyst in the liver (fig. 22). The elliptical, fusiform, rarely pear-shaped or cylindrical bodies of the parasites measured 5 µ to 14 µ in length, and were provided with a flagellum at one end, while the other extremity usually terminated in a long point. An oral aperture occurred at the base of the flagellum, and there were one or two vacuoles near the posterior extremity. Longitudinal division was also observed (fig. 22). As already mentioned, this form, which Lambl termed _Cercomonas intestinalis_, differs considerably from the form found by the same author in 1859, which received the same designation (_cf. Lamblia intestinalis_, p. 60), but it corresponds with _Cercomonas hominis_, Davaine. The latter, as well as _C. intestinalis_, Lambl, 1875, is usually classed with the Trichomonads, but, as has already been remarked (_cf._ _Trichomonas intestinalis_, p. 54), this cannot be considered correct, as only _one_ flagellum is present. _Cercomonas vaginalis_ (Castellani and Chalmers, 1909) was found in the vagina of native women in Ceylon. Other species of _Cercomonas_ have, at various times, been recorded from man. However, the parasitic species of the genus _Cercomonas_ require further investigation. According to Janowski (1896–7), typical Cercomonads have also been observed in the intestine of man by Escherich, also by Cahen, Massiutin, Fenoglio, Councilman and Lafleur, Dock, Kruse and Pasquale, Zunker, Quincke and Roos, and others. However, it is an open question whether the Flagellata observed by Roos in one of his cases belonged to Davaine’s species, the size showing some deviation (14 µ to 16 µ). In his, as in many other cases, doubts have been raised as to whether the flagellates found in the stools had actually lived in the intestine, or had subsequently appeared in the fæces: for this a surprisingly short time only is necessary. Salomon also appears to have observed Cercomonads (_Berl. klin. Wochenschr._, 1899, No. 46).