>' 2 



FIG. I. Diagram illustrating the life-cycle of Entamoeba coli. (After 

 Hartmann.) 1, young amoeba; 2, adult amoeba; 2a, reproduction by simple 

 division; 3, the division of the chromatin of the nucleus into eight groups 

 collected upon the surface of the nuclear membrane; 4, complete nuclear 

 division; 5, schizogony, or division of the amoeba into eight daughter 

 amoebae; 6, commencement of cyst formation; 7, primary division of the 

 nucleus within the cyst; 8, incomplete cell-division and formation of chro- 

 mides; 9, formation by the chromides of two pairing nuclei; 10, formation 

 of two reduced nuclei by each pairing nucleus; 11, division of each of the 

 reduced nuclei into a free nucleus (male) and a stationary nucleus (female); 

 12, two nuclear stage formed by the merging of one free and one stationary 

 nucleus; 13, adult cyst containing eight daughter-nuclei formed by the 

 repeated division of the new nucleus; 14, the adult cyst after reaching the 

 intestine of the host, liberating the eight young amoebae formed during 

 sporogony. 



