CHAPTER VIII 



KARYOKINESIS 



In 187'J. Hermann Fol, writing of the eggs of Geryonia, thus 

 describes the phenomenon of karyokinesis : " On either side 

 of the residue of the nucleus there appears a concentration of 

 plasma, thus forming two perfectly regular star-like figures, 

 whose rays are straight lines of granulations. There are other 

 curved rays which pass from one star or centre of attraction 

 to the other. The whole figure is extraordinarily distinct, 

 recalling in a striking manner the arrangement of iron filings 

 surrounding the poles of a magnet. Sachs' theory is that the 

 division of the nucleus is caused by centres of attraction, and 

 I agree with him, not on theoretical grounds, but because I 

 have actually seen these centres of attraction." 



Since the discovery of Hermann Fol, a great number of 

 explanations have been given, all of them theoretical, to 

 account for the figures and phenomena of karyokinesis. 

 Many of these so-called explanations are mechanical, while 

 others invoke the aid of magnetism or electricity to account 

 for the resemblance of the figures of karyokinesis to the mag- 

 netic or electric phantom or spectre. Among the authors who 

 have dealt with this question we may mention Hartog of 

 Cork, Gallardo of Buenos Ayres, and Rhumbler of Gottingen. 



In 1904 I presented to the Grenoble Congress, and in 

 1 !)()(> to the Lyons Congress, a series of photographs and 

 preparations of experimental karyokinesis. I showed how, in 

 a solution analogous to that found in the natural cell, the 

 simple processes of liquid diffusion, without the intervention of 

 magnetism or electricity, may reproduce with perfect accuracy 

 and in their normal sequence the whole of the movements and 



