1068 PATHOGENIC PROTOZOA 



ical importance. Emetin has a decided effect upon many cases of 

 pyorrhea alveolaris, and under that treatment alone the disease 

 may disappear ; the nature of its therapeutic action is not yet clear, 

 and does not necessarily indicate any etiological relationship. 



ENDOLIMAX NANA (Wenyon and O'Connor, 1917) Burg, 1918 



(Amoeba Umax, Wenyon, 1916. Entamceba nana, Wenyon and O'Con- 

 nor, 1917. Endolimax intestinal, Kuenen and Swellengrebel, 

 1917.) 



This organism was first described in 1917 by Wenyon and 'Con- 

 nor, by Swellengrebel and Mongkoe Winoto, by Kuenen and Swel- 

 lengrebel and by Dobell and Jepps. The last mentioned authors 

 believe it to be the commonest inhabitant of the human bowel. It 

 is agreed by all investigators that it is not pathogenic and that 

 its principal importance is due to the possibility of confusing it 

 with E. histolytica. In the vegetative stage it is quite small, usually 

 measuring 6 to 12 microns in diameter. It usually contains food 

 vacuoles filled with bacteria but no blood cells and never contractile 

 vacuoles. Its movements are sluggish, resembling those of E. coli, 

 the differentiation between ecto- and endoplasm is not clear cut 

 and the pseudopods are few and blunt. Outside the body all move- 

 ment soon ceases. 



The nucleus is seen with difficulty in the living specimen but 

 when the organisms are properly fixed and stained with iron 

 haematoxylin the nucleus becomes the most characteristic feature 

 of the parasite. It is vesicular and 1 to 3 microns in diameter 

 averaging between 2 and 2.5 microns. The karyosome is large and 

 pleomorphic. It consists of a principal mass, which is excentrically 

 located and provided with few or many lobes, which are often 

 almost detached from the main body, being connected only by a 

 narrow isthmus. It is necessary to have well differentiated stains" 

 or the details of structure will be overlooked. 



If the stool is not fresh the amoebae may degenerate and the 

 nucleus present quite a different appearance; the segments of the 

 karyosome can no longer be distinguished and the total mass may 

 come to lie on the outer ring of cliromatin granules, giving rise 

 to a signet ring appearance. It is best therefore to obtain the fresh- 

 est possible material for study, 



