104 STUDIES IN ELECTRO-PHYSIOLOGY: 



" (3) Each of the chromosomes splits longitudinally 

 into two. 



" (4) The fibres separate into two groups, the ends being 

 for a time interlocked," i.e., complete division 

 has not taken place. 



" (5) The two groups pass to the opposite poles of the 

 now elongated nucleus and form a star-shaped 

 figure at either pole (diaster). Each of the stars 

 represents a daughter nucleus." At this point 

 complete separation has occurred, and the following 

 appearance is presented (Fig. 13) : 



Fig. 13. Fig. 14. 



" ( 6 ) ( 7 ) ( 8 )- Each star of the diaster goes through the 

 same changes as the original nucleus, but in the 

 reverse order, viz., a skein, more open and rosette- 

 like, then a closer skein, then a network ; passing 

 finally into the typical reticular condition of a 

 resting nucleus." The penultimate stage is shown 

 in Fig. 14 and is the stage immediately preceding 

 the division of the cell. 



" The protoplasm of the cell divides soon after the 

 formation of the diaster. During division fine lines are 

 seen in the protoplasm, radiating from the centrosomes at 

 the poles of the nucleus, whilst other lines form a spindle- 

 shaped system of achromatic fibres within the nucleus, 

 diverging from the poles towards the equator. These are 

 usually less easily seen than the chromatic fibres or chromo- 

 somes, but are not less important, for they are derived from 

 the attraction-spheres. These with their centrosomes 

 alway initiate the division of the cell ; indeed, they are 



