128 PARASITIC AMOEBA OF MAN. 



Besides the vacuoles and red corpuscles the endo- 

 plasm generally contains pigment granules, crystals 

 of various kinds, and bacteria. In addition there 

 occur small oval bodies giving the reaction of 

 chromatin when stained, which form the chromatic 

 portion of the nucleus of young amoebse which are 

 developing within the parent organism. 



Motility. In fresh specimens of feces Entamceba 

 histolytica is actively motile, much more so than 

 Entamceba coll. This property is rendered possible 

 by the pseudopodia, which in this species are well 

 differentiated, appearing clear, refractile, and firm 

 in consistence. To study the production of the pseu- 

 dopodia it is necessary to keep the specimen at body 

 temperature, and if this is done motility is main- 

 tained for hours. Even in specimens of feces kept 

 at room temperature the motility of this parasite is 

 often retained for a long time, motile amoeba? being 

 sometimes observed after from two to six hours. The 

 rate of motility is of some value in differentiating this 

 species from Entamceba coli, in which motility is 

 always feeble. The mere extrusion of pseudopodia 

 is more rapid, even though progressive motion may 

 not occur, while the division between the ectoplasm 

 and endoplasm is very distinct. 



The shape of the pseudopodia is of importance 

 in the diagnosis of this organism. It will be re- 



