158 The Significance of Sex. [ Feb. 
nuclei are present, and to this form of division the term /ree-cell 
Jormation has been applied, while the term in the sense in which 
Schleiden used it has been pretty nearly abandoned. Still, we 
saw that in the Protozoa nuclei could arise by the fusion of gran- 
ules, and return by fragmentation to the granular state, and it 
may be a question whether similar phenomena may not be found 
in tissue-cells. The cases of the endogenous origin of nuclei are 
reported in eggs that have so much yelk that it is hard to follow 
the nuclear changes. 
Does the cytoplasm or the keelas ilate division? Hertwig 
holds that the nucleus is the automatic centre which controls the 
individuality of the cell, but it must be confessed that the earliest 
changes are in the cytoplasm. Protoplasm gathers at two points 
and forms stars, between which the nucleus becomes stretched 
out and transformed. Carnoy (Fig. 124), and lately (1886) Hert- 
wig, have found independent stars arising in the cytoplasm, and 
if more than two of these get connection with the nucleus, there 
are as many polesand spindles or resulting daughter-nuclei as there 
are asters. The rays about these asters are simply a transforma- 
tion of the reticulum. What their function is we can only guess 
with the numerous guesses made by predecessors. They may 
be nutritive, may be paths for travelling gemmules, may have a 
nervous function, or finally only serve motor functions. The 
spindle-fibres are a similar transformation of the nuclear reticu- 
lum (że. the parachromatin reticulum); whether the nuclear 
membrane in dissolving adds to their material, or gathers at the 
poles of the spindle as in Actinospherium, may be doubtful. 
In the latter case it would continue its original function of medi- 
ating between the intra- and the extra-nuclear reticulum. But 
Strasburger and others find that the astral- and spindle-fibres are 
continuous, and thinks the latter come by a penetration of the 
former through the poles of the nucleus. But the mass of evi- 
dence is against him, and besides, the spindle-fibres are composed 
of parachromatin (chemically, plastin) and react differently from 
the extra-nuclear fibres. 
_ Then there are the polar corpuscles in the centres of the stars, 
and forming the apices of the spindle. Their origin is obscure. 
_ Possibly the plastin nucleolus of Carnoy may, by its division and 
‘migration, have initiated the division of the nucleus, and is rep- 
ee It is ee T o DERA 
