The correctness of Leuckart’s judgment in regard to Marchand-Zunker’s flagellate was demonstrated by Grassi’s researches, accounts of which were published soon after. In about 100 cases of bowel complaints in North Italy and Sicily, Grassi found Flagellata in the stools, which he first named _Monocercomonas_ and _Cimænomonas_, but later termed _Trichomonas_. However, in opposition to Leuckart, Grassi has also classified Davaine’s _C. hominis_ (= _C. intestinalis_, Lambl, 1875) as _Trichomonas_, and most authors have followed his example. Hence arose the use of the name _Trichomonas hominis_. It was through Janowski (1896) that the former view was again taken up. After a review of the literature, the occurrence of Cercomonads in the intestine of human beings in addition to Trichomonads was considered by the author to have been proved, and he added a description of the Trichomonads. According to this, all morphological distinction between _T. vaginalis_, Donné, and _T. intestinalis_, Leuckart, disappeared. On the other hand, it is worthy of note that the smaller size, the more pear-shaped form, and the longer flagella differentiate _T. intestinalis_ (= _T. hominis_) from _T. vaginalis_.[40] [40] For the present the following should be regarded as synonymous: _Protoryxomyces coprinarius_, Cunningham (_Quart. Journ. Micr. Sci._ (2) 1880, xxi, p. 234), (_Zeitschr. f. Biol._, 1882, viii, p. 251). _Monocercomonas hominis_, Grassi, 1882. _Cimænomonas hominis_, Grassi, 1882. _Trichomonas hominis_, Grassi, 1888. _Cercomonas coli hominis_, May (_Deutsches Archiv. f. klin. med._, 1891, xlix, p. 51). _Monocercomonas hominis_, Epstein (_Prag. med. Wochenschr._ 1893, Nos. 38–40). _Trichomonas confusa_, Stiles (_Zool. Anz._, 1902, xxv, p. 689). _Trichomonas elongata_, _Trichomonas elliptica_, Cohnheim (_Deutsche med. Wochenschr._, 1903, xxix, Nos. 12–14). _Trichomonas elongata_, _Trichomonas caudata_, _Trichomonas flagellata_, Steinberg (_Kiewer Zeitschr. f. neuere Medicin_, 1862). _Trichomonas pulmonalis_, A. Schmidt, (_Münch. med. Wochenschr._, 1895, No. 51), and St. Artault (_Arch. de parasit._ 1898, i, p. 279).