20 
SPERMATOGENESIS OF NORMAL 
The Division of the Primary Spermatocyte. 
As soon as the phase of synapsis is past, the nucleus under¬ 
goes a process of reconstruction and the contents are once more 
redistributed throughout the whole internal area. It does not 
pass back into a resting condition, but proceeds at once to the 
development of the spirem. In reconstruction, the linin fibers 
are the first to spring out from the eccentric mass and gradu¬ 
ally extend throughout the nucleus. The chromatin soon 
follows until a large well developed spirem is formed (Fig. 8). 
As in the spermatogonia, the chromatin substance seems to be 
laid down in the form of granules which are imbedded in the 
linin fibres. The granules spread until they are finally about 
equally distributed throughout the linin. In the early stages 
of spirem formation, chromatin nucleoli or net knots are pres¬ 
ent, but they gradually resolve into granules which spread until 
all portions of the spirem are approximately equalized in the 
supply of chromatin. Looked at from certain views, the spirem 
seems to be a continuous thread, but from others it appears as 
a number of closed loops. Whether these loops exist as such 
from the first could not be determined. 
Early in the reconstruction after synapsis, a division of the 
centrosome occurs and one of the new centrosomes moves 
slowly along the outside of the nuclear membrane toward its 
place at the opposite pole of the nucleus. As this centrosome 
advances, a part of the sphere substance spreads around the 
nucleus and accompanies it (Fig. 8). The nuclear wall persists 
as a distinct membrane till late in the preparation for division. 
Concomitantly with the migration of the centrosome, the 
spirem-like appearance inside the nucleus disappears gradu¬ 
ally, until by the time the centrosome reaches its position at the 
opposite pole of the nucleus, the components of the spirem are 
seen distributed through the nucleus in the form of 8 elongated, 
irregularly-shaped rings (Fig. 9). If the saffranin-gentian-vio- 
let method of staining is used, the rings can easily be ■‘-'ver -mder 
high power to consist of a violet groundwork of linin in which 
are imbedded numerous red granules and lumps of chromatin, 
so that the strands have a monilated appearance. Occasionally 
