604 AMCEBIC DYSENTERY 



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 simple amitotic division and also 

 by budding. The entamceba coli is an organism of about the 

 same size. When at rest it shows no differentiation into ecto- 

 plasm 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. 



Both organisms have now been shown to pass into a resting 

 stage with formation of cysts, the character and mode of forma- 

 tion of which are markedly different in the two cases. The cyst 

 formation of the entamceba histolytica, as described by 

 Schaudinn, is specially seen when the disease is in process of 

 cure and the stools are beginning to have a less fluid character. 

 In the earliest stage of the change the nuclear membrane 

 becomes broader and fades into the protoplasm, whilst the 

 chromatin becomes dispersed through the endoplasm in the 

 form of small chromidia. Buds then form on the surface, 

 and into these some of the chromatin passes. Around these 

 buds concentric striation can be seen, and then a hyaline 

 cyst wall is formed, which is highly refractile in character. 

 The cyst then becomes separated from the rest of the cell. 

 Several cysts which measure 2 to 7 ^ in diameter may be formed 

 from the same amoeba, and the remnant of the cell undergoes 

 disintegration. These cysts, as will be shown below, repre- 

 sent a resting-stage with high powers of resistance to external 

 agencies, and are concerned in producing infection of another 

 subject. The cellular changes in the encysting of the entamoeba 

 coli have also been worked out by Schaudinn. They are of 

 a somewhat complicated character, involving the formation 

 of reduction bodies and copulation of nuclei, but the ultimate 

 result is the formation of a fairly large cyst, which contains 

 eight small cells. The process of cyst formation accordingly in 

 the two organisms is of a widely different character. 



The description of the encystment of amoebae from cases of 

 dysentery as given by some other observers differs considerably 

 from that of Schaudinn. In fact, in the majority of the in- 

 vestigations published no process of encystment of buds on the 

 surface of the amoeba has been observed ; on the contrary, the 



