316 



PROTOZOOLOGY 



especially per anum by this amoeba and show typical symptoms. 

 Spontaneous dysentery among cats due to this organism has also 

 been noticed. 



Fig. 145. a-f, Entamoeha histolytica (a, trophozoite; b, precj^stic 

 stage; c, cyst, X1330; d-f, excystment, X930) (a-c (Kudo); d-f 

 (Yorke and Adams)); g, h, E. coli, X1330 (Kudo); i-k, E. gingivalis, 

 X670 (Kudo). 



E. coli (Losch) (Fig. 145, g, h). Trophozoites 15-40jU in diame- 

 ter; cytoplasm indistinctly differentiated; lobopodia slowly 

 formed and movement sluggish; food vacuoles contain var3dng 

 number of bacteria, also erythrocytes in a few cases (Tyzzer and 

 Geiman); nucleus observable in vivo; compared with E. histolyt- 

 ica, the endosome is somewhat larger and located eccentrically 

 and peripheral chromatin granules more conspicuous; multiplica- 

 tion by binary fission; precystic stage very similar in appearance 

 to that of E. histolytica; mature cyst contains normally 8 nuclei 

 and measures lO-SO^u in diameter; in young cysts there are gly- 

 cogen bodies which are comparatively larger than those found in 

 the last-named species; chromatoid bodies splinter-like and often 

 grouped. This amoeba seems to have been observed first by Lewis 

 in 1870 in India. It is a commensal in the human intestine and 

 widely distributed throughout the world. 



