OF THE ALIMENTARY TRACT 119 



specimens both in active and encysted stages the 

 nucleus may be correctly observed and upon this de- 

 pends the identification of the organism. 



The nucleus has an inconspicuous rim on which 

 are no chromatin granules. This material is collected 

 into the karyosome, which is a comparatively large 

 irregular chromatin body or collection of granules, 

 usually well to one side of the nucleus. This body may 

 show a larger granule on one side and a smaller one 

 on the other, connected by a thread. The cyst has 

 four of these characteristic nuclei, commonly in one 

 end of the cyst. 



It may be readily appreciated that the vegetative 

 form may be confused with small sluggish Enda- 

 nioeba histolytica and that the cyst may also be falsely 

 identified as the cyst of that important parasite. 

 One should be warned, however, by the small size, the 

 sluggishness of movement, the shape of the cysts, and 

 the difficulty or impossibility of showing the nuclei 

 even in iodine preparations. Positive identification 

 rests upon stained preparations in which the nucleus 

 can be accurately studied. 



Endolimax nana inhabits the large intestine of man 

 and its visible food bodies are bacteria. Wenyon 

 (1920) saw it in the lumen of mucous glands in sec- 

 tions. The writer (1923) failed to find that it in- 

 vaded ulcers of the rectum in a person who harbored 

 it in the intestine. There is no indication that it 

 ever causes harm to its host. 



Thomson and Robertson (1925) maintained 



