PATHOGENIC AMOEBA 483 



pointed (Fig. 55). Tn the endosarc highly refractile granules 

 occur, and it often contains blood- corpuscles and a vacuole 

 (Fig. 54, 6). A nucleus can also be demonstrated, but 

 being poor in chromatin, it stains with difficulty (Fig. 54, a). 

 According to Schaudinn, the E. coli differs from the E. 

 histolytica in that the ectoplasm is not distinctly seen 

 except during the formation of a pseudopodium, and the 



FIG. 55. Changes in form of an Amosba histolytica observed on 

 a warm stage, and drawn at intervals of one minute. (Semi- 

 diagrammatic by the writer.) 



nucleus stains deeply. The development of the two forma 

 is also different. E. coli multiplies by simple binary fission, 

 and also by multiple fission into eight small amoebae. 

 Encystment may also occur, with repeated binary division 

 of nucleus and protoplasm, part of the nucleus being cast 

 off and ultimately the cyst contains eight nuclei around 

 which the protoplasm collects, so that, if swallowed, eight 

 small amoebae are set free. 



The E. histolytica multiplies by binary fission, and also 

 by irregular gemmation, so that an indefinite number of 



