CHAPTER XXVII 



KARYOKINESIS 



The phenomena of Karyokinesis are essentially exhibitions 

 of Force of Attraction and Repulsion in action within the 

 confines of the enlarged cell, and it is owing to the act of 

 mass-repulsion finishing the process of division that con- 

 tinued growth, and advance towards the restoration of the 

 sexual elements, are made possible. The restoration is a 

 very gradual process, judging from the large number of 

 division acts preceding it, but while this is so, there seem 

 to be certain definite stages attained on the road which 

 are indicated by variations in the nuclear division-phenomena 

 exhibited. Thus, in the main road of the growth-cycle 

 three forms of Karyokinesis can be observed : — 



I. Karyokinesis with double chromosomes. 

 II. Karyokinesis with single chromosomes. 

 III. Karyokinesis as exhibited in the extrusion of Polar 

 Bodies. 



Karyokinesis with double chromosomes may be described 

 briefly as follows : — 



The nucleus of the cell about to divide loses its retiform 

 character and takes the appearance of a thick convoluted 

 chromatin thread, coiled compactly (Fig. 84, c). The 

 nuclear membrane and nucleolus disappear. The convoluted 

 thread disentangles itself to a certain extent, and breaks 

 into a number of short lengths (the number being fixed 

 for the organism in question), each of which becomes bent 

 to form a loop. The loops arrange themselves in the 

 equatorial plane of the cell with their. free ends pointing 

 outwards, forming thus a species of rosette. This is called 

 the " monaster " stage (Fig. 84, e). 



Meanwhile at the opposite poles of the cell a point defines 



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