AMCEB.E OF THE INTESTINAL TRACT. 209 



about seven-eighths of the organism, is light gray in 

 color, very refractive, and granular in structure, the 

 granules being much coarser than in Entamceba his- 

 tolytica or in Entamceba tetragena. The endoplasm 

 always contains non-contractile vacuoles of various 

 size. 



The Nucleus. The nucleus is always visible as a 

 well defined spherical body, measuring from 5 to 7 

 microns in diameter, and situated near the centre of 

 the parasite. A very delicate but distinct nuclear 

 membrane surrounds the nucleus. The chromatin is 

 large in amount and occurs in masses upon the inner 

 surface of the nuclear membrane, there being no 

 chromatin whatever distributed through the nuclear 

 plasma. During the vegetative stage the chromatin 

 appears as refractive masses varying in shape which 

 lie upon, or are attached to, the nuclear membrane. 

 Sometimes they are crescent or spindle shaped and 

 lie lengthwise upon this membrane or they may be 

 attached to it by delicate fibrils. The masses of 

 chromatin vary in number from 3 to 8, according 

 to the age of the parasite, being more numerous in 

 the older organisms. 



Vacuoles and Contained Bodies. A contractile 

 vacuole is not present in this species, but the endo- 

 plasm always contains one or more non-contractile 

 vacuoles which vary in size. In cases where the feces 



14 



