ELEMENTS OF HISTOLOGY. 



[Chap. 



process of karyokinesis is represented in the adjoin- 

 ing figure, 5, and it consists of the following phases : 

 (a) The nuclear network become very pronounced, 

 while the nuclear membrane disappears, and the 

 fibrils of the nuclear network becomes twisted and 

 bent into a more or less dense convolution; at the 

 same time the nucleus, as a whole, is considerably 

 enlarged, (b) The fibrils unravel into loops, arranged 







Fig. 5. Karyokinesis. 



A, Ordinary nucleus of a columnar epithelial cell ; B, c, the same nucleus in the 

 stage of convolution ; P, the wreath, or rosette form ; F, the aster, or single 

 star ; F, a nuclear spindle from the Deseemet'i endothelium of the frog's 

 cornea ; G, H, i, diaster ; K, two daughter nuclei. 



around the centre as a wreath or rosette, (c) The 

 peripheral points of the loops become broken, and 

 we obtain a star-shaped figure of single loops the 

 aster, (d) The loops separate into two groups or 

 new centres : this is the diaster, or double star. 

 (e) The two groups of threads become further apart, 

 as if attracted by opposite poles ; but the two groups 

 remain still connected with one another by fine pale 

 threads. These latter differ from the others in not 

 staining with certain dyes, and representing the in- 



