136 BULLETIN OF THE 
others with a single nucleus that are actually larger than the former 
(compare the cells in Figure 14). In such cases, the single nucleus is 
always larger than the daughter nucleus of the other cells. I am unable 
to see that multiplication of nuclei in the cell leads to any immediate 
increase of nuclear material. The more they divide, the smaller they 
become. Probably the most important office of division is a more 
extensive distribution of nuclei throughout the cytoplasm, with correspond- 
ing increase of nuclear surface; and this, considering the great superfi- 
cial extent of the cells, and the comparatively small size of the nuclei 
(at least in the older membranes) must be a matter of some importance 
for the activities of the cell. It is especially so in the case of elongated 
cells. If such cells have but a single nucleus, a large part of the 
cytoplasm must be remote from it; and if the nucleus is at the centre 
of the cell, the cytoplasm at the ends of the cell will be most remote, 
So, to restore the equilibrium between cytoplasm and nuclei, the nucleus 
must elongate in the longitudinal axis of the cell, and the daughter 
nuclei move toward the ends of the cell. 
As a matter of fact, nearly all elongated cells have two nuclei, and 
these lie in the long axis of the cell, usually rather nearer its ends than 
toeach other. It cannot be denied that many short or squarish cells 
also contain two nuclei; and, conversely, a few much elongated cells 
can be found that have but one. In the latter case, it is interesting 
to observe that almost invariably the nucleus has begun to elongate 
in the longitudinal axis of the cell, and is often far advanced towards 
division. We can say almost with certainty, then, that such cells are 
of recent formation, and that the equilibrium between cytoplasm and 
nucleus is promptly restored by division of the latter. Itis true that 
cases like that represented in Figure 12, where nuclear division takes 
place in the short axis of an elongated cell, cannot be explained in this 
manner. Such instances are so rare that they might almost be con- 
sidered as abnormal; but the difficulty of the matter lies in the fact 
that we get all gradations between nuclei ranged in the true longitudi- 
nal axis, and those placed in the transverse axis. It is common to find 
them lying more or less obliquely in the cell, though the obliquity is 
seldom so great as to prevent them from practically fulfilling the con- 
ditions of the hypothesis, 
It is not supposable that all the agencies impelling nuclei to divide, 
and controlling the direction in which division shall take place, reside 
in the cytoplasm ; possibly the most potent of them exist in the nucleus 
itself. That axial differentiation, with definite pole and antipole, is as 
