198 PARASITIC AMCEB^E OF MAN. 



of f eces we observe amoebae showing sluggish motility, 

 no distinction between the ecto- and endoplasm, or a 

 very slight distinction, and the presence of a nucleus 

 having a well defined nuclear membrane and con- 

 taining much chromatin, we may diagnose the 

 organism as Entamceba coli; under the same con- 

 ditions, if we observe an amoeba which is actively 

 motile, presents a clear, glass-like ectoplasm sharply 

 distinguished from the endoplasm, and a nucleus hav- 

 ing a well defined nuclear membrane and a clear area 

 surrounding the centriole, the diagnosis will be Enta- 

 mceba tetragena; finally, if an actively motile amoeba 

 is observed, showing a clear distinction between the 

 ecto- and endoplasm (the former being clear and 

 glass-like in appearance) while a nucleus is absent, 

 or if present, shows no nuclear membrane and but 

 little chromatin, the diagnosis will be Entamceba his- 

 tolytica. 



Stained Preparations. In well stained prepara- 

 tions with Wright's stain the three species may be 

 distinguished by the staining of the ecto- and endo- 

 plasm. In histolytica the ectoplasm stains more in- 

 tensely than does the endoplasm, while the opposite 

 is true in Entamceba coli. In Entamceba tetragena 

 there is but little distinction between the staining 

 reaction of the ecto- and endoplasm. In stained 

 specimens showing the reproductive forms the various 



