SARCODINA 735 



much more fluid than in histolytica. The digestive vacuoles rarely 

 contain red blood cells, but are filled with cocci and bacilli, a form of 

 food rarely seen in histolytica. In general, the vacuoles are larger 

 and more numerous in coli than in histolytica, and the motility is 

 feebler. In fresh specimens the nucleus is rather easier to find than 

 in histolytica, and is distinctly outlined by a heavy, double-contoured 

 membrane. The nucleus, as in all ameba, is vesicular, and shows a 

 small karyosorne and dots of chromatin on the nuclear membrane and 

 imbedded in the nuclear network. 



FIG. 164. ENDAMEBA COLI CYST. (Army Med. School Collection, 

 Washington, D. C.) 



Multiplication in the vegetative stage is- by binary fission of the 

 nucleus and the cytoplasm, resulting in two daughter cells, or the 

 nucleus may continue to divide into four or eight daughter nuclei 

 before the cytoplasmic division begins, producing, in the end, two, 

 four, or eight daughter cells. 



Cyst Formation. This is characteristic of the species, and it fur- 

 nished one of the principal reasons for Schaudinn 's separation of coli 

 and histolytica. Before encysting the animal frees itself of all in- 



