OF THE ALIMENTARY TRACT 149 



for a time before the organisms swim separately. 

 By this time the complement of organelles of each 

 is usually complete. Such division may be watched 

 in cover glass preparations from cultures. 



If Trichomonas hominis ever encysts it is un- 

 known. The writer (1915 and 1916) erroneously de- 

 scribed two cysts for the organism, the first was 

 Blastocystis, which had been so described by Ucke 

 (1908), by Bohne and Prowazek (1908), and Bensen 

 (1901). The second, an original error, was the cyst 

 of Chilomastix mesjiili, not well known at that time. 



HABITAT AND EFFECTS 



The natural habitat of the intestinal Trichomonas 

 is the colon, particularly the caecum. 



After ingestion it passes through the stomach and 

 small intestine but probably does not become seated 

 until it reaches the caecum. 



It is apparently solely a lumen dweller. Wenyon 

 (1926) found it once in the lumen of the glands of 

 the large intestine and passing from the glands into 

 the interstitial tissue. He states that the intestinal 

 Trichomonas of the guinea pig, Trichomonas caviae, 

 often invades the wall of the large intestine, which 

 shows ulceration, in that animal. Wenyon thinks 

 that tissue invasion may occur and cites the observa- 

 tions of Pentimalli (1923), who found the organ- 

 ism in, the blood, and Kessel (1925), who saw it in the 

 pus of an amoebic liver abscess, but does not know 



