148 The Significance of Sex. [ Feb. 
year the first edition of Stvasburger’s work on cell-division ap- 
peared. This treated in the main of the plant-cell, where the 
spindle thickenings after separating leave between themselves 
connecting fibrils that are more prominent than in the animal- 
cell. These he called xuclear fibrils, and at their equator a second 
set of thickenings appear that go to construct the dividing wall 
between the new cells, hence he named it the cedl-plate. The 
second edition of this work appeared in 1876, and the third in 
1880. In the last he changes the name he gave the connecting 
fibres to cell-fibres, because he supposed that they were formed 
from the ‘cytoplasm penetrating into the nuclear matter at the 
time of the deconstitution of the latter. 
Van Beneden, on the other hand, agreed with Bütschli that the 
spindle comes from the old nucleus. He distinguishes between 
the nuclear sap and the xuclear essence. The connecting fibrils are 
of the same essence as the nuclear disk, and are due to the draw- 
ing out of the elements as they segment into the daughter-disks. 
In this year, also, Hertuig showed that the egg-nucleus does 
not disappear during cleavage, but passes through a metamorpho- 
sis similar to the cell-divisions described by Bütschli. At the 
poles of the spindle and in the centre of each aster he finds a 
polar corpuscle. Fol had seen corpuscles in the stars, but had 
confounded them with the daughter-nuclei. The following year, 
1876, Fol corrects this error. Balbiani found the nuclear plate to 
be composed of rod-like elements that were composed of granules, 
but these views were unnoticed, so that Pfitsner received the 
honor of their discovery five years later. 
At this time the elements which compose the nuclear plate 
-= were not distinguished from the spindle-fibres, due to the fact 
that reagents which made the one visible left the other obscure, 
hence there was a good deal of contradiction in the results, 
which was unreal. 
In this year Bitschi’s chief work appears. He supposes the 
-infusorian ‘nucleus to represent the original type of nucleus. He 
thinks the cytoplasm stimulates the nucleus to division, though 
it may not itself necessarily follow the example. The rays of the 
stars are not the expression of attractive forces of the nucleus, 
T mie toa Shona influence. He found that the 
