ENDOLIMAX NANA 



E. coli. No careful experiments have been carried out to 

 determine just what happens to coH cysts within the di- 

 gestive tract of foreign hosts. 



2. ENDOLIMAX NANA 



This species appears to be a harmless commensal that 

 lives in the large intestine of man, although its exact loca- 

 tion in the human host is not known. About 25 per cent 

 of the general population have been found to be infected. 

 The cysts are apparently responsible for the infection 

 of new hosts and since they probably differ from those 

 of E. histolytica in no essential feature with respect to 

 transmission, etc., and, since our knowledge of them is 

 even more meager than that of histolytica cysts, it seems 

 useless to discuss them here. No evidences of patho- 

 genicity have been discovered; Wenyon (1926) has re- 

 ported them from the lumen of the intestinal glands but 

 there were no signs of tissue invasion. Hegner (1927b) 

 has described the excystation of Endolimax nana in 

 vitro. 



Species belonging to the genus Endolimax occur in 

 certain lower animals. Amoeba-like organisms that have 

 been described from the malpighian tubules of rat and 

 dog fleas and in the vagina of the leech may be species 

 of Endolimax. The frog, domestic fowl and monkey also 

 seem to be infected with members of this genus. Tyzzer 

 ( 1920) described as Pygolimax gregariniformis a species 

 that he found in the cecum of fowls. Hegner (1926a) 

 redescribed this species as Endolimax janisce. Tyzzer's 

 specific name is valid but the organism undoubtedly be- 

 longs to the genus Endolimax. Very few attempts to 



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