1887] The Significance of Sex. 151 
Pfitzner, this year, called attention to the fact that the nuclear 
loops are composed of granules like a row of beads, and that the 
loop splits by the segmentation of each granule. He thought 
these granules to be the protoplasmic molecules, but later (1883) 
said they were independent and individual units in the. nuclear 
structure. (See Fig. 114, a, 6.) 
In 1882, Strasburger proposed the terms cytoplasm, microso- 
mata, nucleoplasm, etc., which we adopted in Section æ of this 
paper. He studied more carefully the method of rearrangement 
of the loops in the equatorial plate during its division, and finds 
that it is more complex than Flemming made it, for the old bend 
straightens out, and one end of the loop gets drawn towards the 
pole, and then bends like a hook, and this new bend travels along 
the filament to its middle point, thus making the two limbs equal, 
while at the same time the loop is drawn polewards. Strasburger 
had not yet discovered the splitting of the loops, so that he had 
as yet only an imperfect notion of how the rearrangement took 
place. (See Figs. 118 and 119 for the actual facts.) 
In this year appeared Flemming’s systematic work on the cell, 
and in it he accepts the criticisms of Retzius and Strasburger, so 
far as they relate to the rosette phase and the “ rearrangement.” 
He doubts if there is a reticulum in cells, or at least in nuclei. 
The appearance.may be due to the optical effect of a closely- 
wound filament or mitom, the sap is the paramitom, and karyo- 
kinesis should be termed mitokinesis, or mitosis. Besides the 
mitom there are chief and accessory nucleoli. He gives up the 
idea that the chromatin may dissolve in the cell-sap. He gives 
us the term sgzrem for the knauel phase. Rearrangement in the 
equatorial plate is termed metakinesis. He uses the term aster 
for the star-form of the mother-nucleus, and dyaster for that of 
the daughter-nucleus. 
In 1883, Pfitzner makes three sorts of chromatic substance in 
the nucleus. The substance of the spindle, hitherto called achro- 
matic, he terms parachromatin, while the sap only is true achro- 
matin. The nucleolus has prochromatin, while the mitom has 
the true chromatin. In the resting nucleus there may be, besides 
Strasburger’s membrane, which belongs to the cytoplasm, a true 
nuclear membrane of parachromatin. 
Roux, in this year, proposes a theory of karyokinesis, based 
on the idea that there is a mixture of qualities in the chromatin, 
