90 PARASITIC AMOEBA OF MAN. 



color. While this may be the reason for the greenish 

 coloration frequently observed in Entamceba histolyt- 

 ica, it certainly does not apply in the case of En- 

 tamceba coli, for the addition of blood to the feces 

 containing this organism does not result in the ab- 

 sorption of either dissolved haemoglobin or the 

 phagocytosis of red blood corpuscles. 



It is extremely difficult to describe the exact color 

 of this parasite, but to one who has studied the various 

 species of amoebae the difference in the coloring of 

 Entamceba coli and the pathogenic amoebae is quite 

 characteristic. 



Cytoplasm. The cytoplasm of Entamceba coli is 

 divided into an ectoplasm and an endoplasm. These 

 two portions of the cytoplasm are exceedingly difficult 

 to distinguish in all stages of the growth of the para- 

 site, and impossible unless the organism is in motion, 

 and in many specimens the ectoplasm cannot be dis- 

 tinguished from the endoplasm even when the parasite 

 is actively motile. Schaudinn first called attention to 

 this point and to the fact that the ectoplasm of En- 

 tamoeba coli is much less refractive to light than is 

 the endoplasm, in those instances in which the two 

 portions can be distinguished. 



The ectoplasm presents a homogeneous appear- 

 ance and unless a high power lens is used no definite 

 structure can be distinguished ; with an immersion lens 



