TRANSACTIONS OF SHCTION D. 611 
will be the induction, and the more chauce there is of such interlacings. Their 
presence in cell-figures has been a great difficulty on all interpretations. 
Variant 5.—The existence of 3-asters has been another difficulty. A fair 
5-aster is obtained by arranging unlike poles at the base of an obtuse-angled 
triangle and a core at its vertex. With chains of greater or a medium of lesser 
permeability the yelative distances would be more nearly equalised. 
Variant 6.—-If we alternate two unlike poles and two cores we obtain a 
4-aster, with the centres connected by consecutive spindles and a cross-spindle 
connecting the unlike poles. Such figures are not uncommon in the literature of 
the dividing cell. 
Other variants are shown and compared with their cytoplasmic analogues. 
Leduc has shown that centres of greater and of less concentration respectively in 
a solution give rise to diffusion fields of force, and that like centres of concentra- 
tion (as might have been deduced @ prior?) behave as ‘like’ electric or magnetic 
poles, while only ‘ unlike’ centres give the spindle figure. As it has been shown 
(notably by Vejdovsky) that. the diffusion phenomena in the cell are similar in 
both centres, the force producing the dumbell field cannot possibly be that of 
diffusion. 
We may call all the forces at work in acell undergoing division ‘karyokinetic 
forces.’ But the special force to which the cellular field is due cannot be termed 
‘ karyokinetic force ’ in the singular, because it is operative while the nuclear wall 
is still intact; and the nuclear contents only become affected thereby after the 
wall has disappeared and the nucleus has lost its independence. We may distin- 
guish the force here discussed as ‘ cytokinetism’ or ‘ mitokinetism.’ It is certainly 
not magnetism, since the poles are isolated; and very possibly it is distinct from 
statical electricity. 
4, Demonstration of Cytoplasmic Figures in Segmenting Eggs of Ryn- 
chelmis (Prof. Vejdovsky). By Professor Marcus Harroe. 
RR 2 
