Amebic Dysentery 



67s 



It is accomplished by a peculiar nuclear budding, by which chromatin 

 granules or chronidia are pushed out from the nucleus toward the 

 ectoplasm, where they develop into new nuclei, about which the 

 cytoplasm collects until a distinct bud is formed and cast off as a 

 small but distinct new organism — a spore or bud. These when 

 separated are round or oval, measure 3 to 6 // in diameter, and are 



Fig._ 266. — Reproductive cycle of parasitic ameba (Wenyon). The small 

 circle indicated by i, 2, 3, 3' and 3" indicated multiplication by schizogony, or 

 binary division. The large circle indicated by 1-12, the sporogeny or sexual 

 cycle. The ameba having arrived at its full size (3) becomes enycsted (4). The 

 nucleus then divides into two (s), each half expels a small fragment of nuclear 

 material (6), and when this has been effected, they conjugate (7) forming a 

 synkaryon. The synkaryon then divides into two, into four, and then generally 

 into eight (8-9-10-11-12) when the cyst ruptures, "the spores are liberated 

 (i) and both cycles are again started. 



surrounded by a yellowish envelope, which resists drying and the 

 penetration of stains and chemicals. 



Craig gives a tabulation of the differential feature's of Entamoeba 

 coli. Entamoeba histolytica, and Entamoeba tetragena (vide infra). 



3' Entamoeba Tetragena (Viereck*).- — This organism resembles 

 Entamoeba histolytica more than Amoeba coli, but differs from it 

 m the mode of reproduction, the sporocysts containing four instead 

 of eight spores. 



* "Archiv. f. Schiffs. u. Tropenhygiene," 1907, 11, i. 



