PARASITIC AMGEBJE OF MAN. 



A well defined nuclear membrane cannot be dis- 

 tinguished, the border of the nucleus being of the 

 same refraction as the hyaloplasm. By very careful 

 focussing it is sometimes possible to demonstrate a 

 very delicate limiting membrane, slightly more re- 

 fractile than the rest of the nucleus. 



The amount of chromatin contained within the 

 nucleus of Entamoeba histolytica is much less than 

 in the nucleus of Entamoeba coli. A small chromatic 

 zone is frequently present at the border of the nucleus 

 and a few minute granules are sometimes observed 

 within the hyaloplasm, but this is in marked con- 

 trast to the nucleus of Entamoeba coli, in which the 

 chromatin is distinctly visible, both as well defined 

 elevations upon the inner surface of the thick nucleus 

 membrane and as masses of granules within the hyalo- 

 plasm. The relative proportion of chromatin and its 

 arrangement is well shown in the specimens stained 

 by Wright's method, which will be described later. 



A karyosome is situated near the centre of the 

 nucleus and is very small and delicate in appearance. 



The nucleus is most easily observed in young 

 amoebae and the reason for this is demonstrated in 

 stained specimens where it is noted that in the larger 

 amoebas the chromatin of the nucleus is distributed to 

 the cytoplasm, the remainder of the nucleus forming 

 a residual body, irregular in shape, which it would 



