KARYOKINESIS 253 



like two little magnets with similar poles facing ; the 

 resultant lines of opposing force being made evident by 

 protoplasmic granules, in much the same way as occurs 

 with iron filings in the field between the opposing similar 

 poles of two steel bar magnets. 



And now if we imagine an object, composed of two 

 classes of elements closely blended together, one of which 

 is peculiarly attractable to one pole and the other to its 

 opponent, to be placed in the equator of the magnetic 

 field ; and if we take it that the " elements " are evenly 

 represented and that the poles attract with equal force ; 

 then it is clear that the object would remain suspended, 

 as it were, at the equator. 



But if in addition we suppose that though closely 





Fig. 88. — Diagram of the magnetic field between similar poles. 



blended the two varieties of " elements " were free to move 

 within the confines of the object, then the result would 

 be a determination of one variety to the aspect of the object 

 facing one pole, and of the other variety to the opposite 

 side. This is represented very diagrammatically in Kg. 89. 



It is suggested that this imaginary experiment supplies 

 us with an explanation of the phenomena of karyokinesis, 

 and that although the exact nature of the nuclear separation 

 process must remain a mystery, it is according to the principle 

 illustrated that chromosome splitting occurs. 



It is also possible to explain roughly on the same lines 

 the nuclear phenomena preceding chromosome splitting. 

 The nucleus is not a flat object, but a more or less spherical 

 one ; and it is not unlikely that the first effects of achromatic 



