THE CELL. 



41 



an active change in the shape of the nucleus, which may have pre- 

 viously increased in size and become richer in chromoplasm. The 

 nucleus becomes constricted and finally separated into two portions, 



Fig. 19. 



Epithelial cell from a carcinoma. (Galeotti.) The centre-some has divided into four portions,, 

 and the chromosomes are arranged with reference to these. The figure represents the meta- 

 kinetic phase of karyokinesis, which will result in the formation of four imperfect 

 nuclei. 



which are not necessarily equally rich in chromoplasm. The cyto- 

 plasm, either at the same time or later, becomes similarly con- 

 stricted until it is divided into .two parts, each containing one of 

 the nuclear divisions (Figs. 20, 21, 22). 



Fig. 20. 



Fig. 21. 



Fig. 22. 



Amitotic cell-division. (Flemming.) Epithelial cells from the bladder of a salamander. 

 Figs. 20 and 21 contain nuclei with constrictions dividing them into nearly equal portions. 

 Fig. 22.— Contiguous cells, each containing a nucleus about half the size of those prevailing- 

 in the tissue, and, therefore, probably the result of cell-division by the direct process. 



It is believed that this mode of division does not result in the 

 formation of cells that have the complete character of the parent- 

 cell, and that their descendants form a degenerate race that is 

 destined to extinction. It is quite obvious that no such precise 

 .partition of the chromatic substance is likely to take place as that 



