NUCLEAR DIVISION WITHOUT CELL-DIVISION. 1/3 



while the remotest portion of the liquid assumes a charge of the 

 same sign as that of the charged body. The liquid, in other 

 words, behaves as if it contained charged bodies free to move 

 (ions) which may be separated by the inductive action of an elec- 

 trostatic charge, ions of opposite sign moving toward, those of the 

 same sign away from the inducing charge. 



In the cell the charged body on the above theory is repre- 

 sented by the chromatin ; by the inductive action of its negative 

 charge the anions are repelled toward the periphery of the egg 

 while the kations are attracted toward the nucleus. The center 

 of the astral radiations must on this view represent the region of 

 highest positive potential - -the region, that is, in which the ka- 

 tions are most densely aggregated. Exactly why there should 

 be tu<o such regions, and why these are situated on opposite 

 sides of the nucleus and at some distance from the surface of the 

 latter are questions of considerable difficulty which cannot be 

 considered in detail in the present paper. It is evident that the 

 conditions of electrostatic equilibrium in such a structure as the 

 cell must be of somewhat complex nature. Later I hope to 

 consider these and other questions in fuller detail ; for the present 

 their treatment is deferred. 1 



1 1 may suggest here briefly that the form of the cell must influence the distribu- 

 tion of the surface charges ; and that it is for this reason that the direction of the 

 spindle-axis bears certain well-defined relations to the principal axis of the cell ; these 

 relations have long been known and are formulated in Hertwig's laws of cell-division. 

 If the cell possesses approximately the shape of a prolate ellipsoid a not infrequent 

 condition it is to be expected that the repellent action of the internal negative charge 

 will produce a tendency toward aggregation of anions at those regions of the surface- 

 area which are mo-it remote from the central charged body, i. e. , which adjoin the long 

 axis of the cell. If the surface negative charge so induced attains sufficient density in 

 these regions there must result a tendency for internally situated kations to be attracted 

 toward the poles of the cell as well as toward the chromatin ; kations will therefore 

 tend to collect in each half of the cell in a certain position of equilibrium at which 

 these opposing tendencies are balanced ; the position of these regions will vary with 

 variations in the electrical condition of the chromatin, but will typically be somewhere 

 between the chromatin and the extremities of the long axis of the cell. The astral 

 centers represent these regions of highest positive potential ; hence they form the cen- 

 ters toward which the electrical lines of force converge. Under the usual conditions 

 they are two in number and adjoin the long axis of the cell. The positions of the two 

 may coincide at their earliest appearance ; hence an originally single aster, situated in 

 close proximity to the nucleus, appears to divide into two which recede toward opposite 

 poles of the cell. 



