538 



AMCEBIC DYSENTERY 



in the form of rounded, oval, or pear-shaped cells, measuring 

 12-30 /*. in diameter. When at rest a somewhat clear, highly 

 refractile ectoplasm and a granular endoplasm can be distin- 

 guished, a feature which differentiates the organism from the 

 entamoeba coli. The nucleus is rounded, or oval, and is seen 

 with difficulty ; its position is usually eccentric and is sometimes 

 quite at the margin of the ectoplasm. In the fresh condition, 

 and especially when examined on a warm stage, the organism 

 shows very active amoeboid movements. The pseudopodia, which 

 are quickly protruded and retracted, are blunt and appear to be 

 of tough consistence (Fig. 166), a property which Schaudinn 

 considers of importance as enabling the organism to penetrate 

 the mucous membrane, etc. The amoebic movements are often 



14 



FIQ. 166. Amoebse of dysentery. 



a and b, amuebie as seen in the fresh .stools, showing blunt amoeboid processes of 

 ectoplasm. The endoplasm of a shows a nucleus, three red corpuscles and numerous 

 vacuoles ; that of b, numerous red corpuscles and a few vacuoles. 



c, an amoeba as seen in a fixed film preparation, showing a small rounded nucleus 

 (Kruse and Pasquale). xGOO. 



of an active kind and locomotion may be fairly rapid ; not 

 infrequently red corpuscles, bacteria, cells, etc. may be seen in 

 the interior. The organism usually dies and undergoes disinte- 

 gration in a comparatively short time after being removed from 

 the body ; the stools ought therefore to be examined in as fresh 

 a state as possible. Multiplication takes place by simple amitotic 

 division and also by budding. The entamoeba coli is an organism 

 of about the same size. When at rest it shows no differentiation 

 into ectoplasm and endoplasm, and the nucleus, usually situated 

 in the centre, shows a highly refractile membrane with chromatin 

 masses scattered in the interior. During amoeboid movement 

 some delicate processes of ectoplasm come into view. 



