AMOEBJE OF THE INTESTINAL TRACT. 89 



shape continually changes, depending upon the con- 

 tour of the pseudopodia, but the latter are always 

 rounded, and never spinose, as are the pseudopodia 

 of many of the amoebae cultivated from external 

 sources. The writer has never observed an amoeba 

 in the feces having spinose pseudopodia, although 

 free-living forms must frequently occur in the feces, 

 especially in tropical countries, but probably in the 

 encysted stage. 



The shape of the pseudopodia is useful in differ- 

 entiating this species from the pathogenic amoebae, 

 such as Entamoeba Tustolytica and Entamoeba tetra- 

 gena. In the latter parasites the pseudopodia are 

 generally finger-like in shape and of considerable size, 

 while in Entamceba coli they are short and blunt. 

 Aside from this characteristic of the pseudopodia, the 

 shape of the organisms is of no value in the differen- 

 tiation of species. 



Color. Entamoeba coli may be said to be of a 

 peculiar dull grayish color, and this is of some value 

 in the differentiation of the species, the pathogenic 

 amoebae of the intestine appearing slightly greenish 

 in color or almost colorless. Musgrave and Clegg be- 

 lieve that color simply means environment, the green- 

 ish color being due to the absorption of blood serum 

 containing haemoglobin, and that in feces in which 

 blood is not present the amoebae never present this 



