FORMS OF FNTAMCEB.F 



643 



importance, as enabling the organism to penetrate the mucous 

 membrane, etc. The amoebic movements are often of an active 

 kind, and locomotion may be fairly rapid ; and red corpuscles, 

 bacteria, cells, etc., may often be seen in the interior, though the 

 ingestion of red corpuscles is by no means a constant feature. 

 The organism usually dies and undergoes disintegration 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 division into two and, 

 according to some descriptions, also by budding. Schaudinn 

 considered that the former was a direct division, but Werner 

 and Craig have found that it is of mitotic nature. As the 



,-so^-S^v, 



FlG. 188. —Entamoeba histolytica as seen unstained in tieees in dysentery. 



(a) Large entamoeba showing blunt pseudopodium of ectoplasm ; in the 

 endoplasni, besides the nucleus there are seen two red corpuscles and a 

 vacuole containing bacteria. 



(0) Smaller binucleate entamoeba, with a single red corpuscle in the interior. 



(c) Encysted entamoeba, containing four nuclei and a chromidial body. 



(The distinctness of all the nuclei has been somewhat accentuated to show- 

 details.) x about 1000. 



(From drawings by Dr. .1. L. Thompson.) 



symptoms of the disease abate, the entamoebas undergo certain 

 changes, which ultimately result in their encystment. The 

 cysts, which are formed when the stools begin to regain their 

 faecal and formed character, are relatively small, measuring 

 10-15 ix in diameter ; the cyst wall is thin, and within it four, 

 or sometimes only two, nuclei can be faintly seen in the fresh 

 condition (Fig. 188, c). In stained specimens the nuclei have the 

 chromatin at the periphery as in the active entamoebas, but are 

 relatively richer in chromatin. Beside the nuclei one or more 

 elongated chromidial bodies may be seen. Such cysts may be 

 found in the faeces for a long time after dysenteric symptoms have 

 disappeared, and as they are the means of infecting other persons 

 the individuals passing them are to be regarded as carriers danger- 

 ous to the community. In the transition from the active amoeboid 



