No. 2:]) SPINWVING ACTIVITIES OF PROTOPLASM, 387 
Further, there is present and visible under these lower powers, 
and capable of “ preservation,” a perfect, pellicle-like covering 
of ectosarc-like substance which under quite high powers may 
show only such surface roughening as would pass as finely 
granular, or seem smooth even, and yet be extending itself all 
the while in hundreds of processes which are most powerful 
determining factors in the scheme of development. 
In the case of the polar bodies as in the cell division, it 
becomes plain that the separation or isolation of portions of its 
substance by the developing egg is but an optical illusion; and 
that the space separation between sister cells, which has been 
taken to be actual and complete and unbridged by living sub- 
stance, and that cavity or space between all the cells of the 
blastula known as the cleavage cavity; are deceptive in the 
highest degree, being in fact bridged by all the cells concerned 
by means of extensions of their living substance. 
At all times the cleavage of the mass of these eggs into por- 
tions which simulate units, is seen to be but a mask for actual 
continuity of the substance of the whole throughout all its 
subdivisions in cell form. 
More than this, the cell substance is seen to have some sort 
of deliberateness, or purpose, in its spinning activities, for 
where the space between blastomeres is artificially increased far 
beyond the accustomed limit, it hastens to cross by unaccus- 
tomed degrees of extension, not resting till it has reached the 
missing masses and reéstablished union with them. 
A reasonable summing up of the phenomena described, — 
weighted by a host of subtle, modifying and restraining evi- 
dences which in such delicate phenomena must always exist 
over and above the description, — would seem to be as follows. 
The facts point to a physiological drawing together of the 
cells, rather than to any physical and chemical “cyto-tropismus”’ : 
To a physiological, rather than a physical reaction to me- 
chanical stimulus of pressure or shaking : 
To a physiological, rather than a physico-chemical, cause of 
the spinning activities : 
To actual and physiological communion as well as physical 
connection between cells after and during their formation : 
