14 
SPERMATOGENESIS OP NORMAL 
globule. In some cases a few of the loops may be. in the form 
of apparent rings even at the equator. The distance between 
the centrosomes increases somewhat as the division proceeds. 
In the division ’of the spermatogonia, the general appear¬ 
ance of the spindle and the arrangement of the chromatin in 
loops seems to be much the same as that of the ordinary tissue 
cells of the pigeon as exemplified in leucocytes and the cells of 
the liver, adrenal and kidney. The chromosomes are crowded 
together so closely and the loops so irregularly disposed as to 
render an accurate count very difficult. Repeated attempts at 
counting both before and after the equatorial plate stage point 
to sixteen as the correct number. 
After division the mass of chromatin becomes so fused to¬ 
gether and dense in appearance as to prevent any determina¬ 
tion of the details of nuclear reconstruction. At each pole a 
clear area is maintained between the centrosome and the 
chromatin for some time while the nuclear membrane is form¬ 
ing on the side of the latter which faces the equator but the 
centrosome is finally lost to view and can not be seen again. 
When a centrosome appears later in the sphere substance of the 
spermatocyte it seems to be generated anew. 
A system of connecting fibers extends from one nucleus to 
the other for a time; as preparations for complete, cell-division 
advance they converge towards the equator more and more. 
A distinct intermediate body or “zwischenkorper” is visible, 
marking out the path of the approaching cytoplamic division. 
The persisting threads often show small varicosities or gran¬ 
ules which react to reagents like the centrosome and mid-body. 
During the nuclear division the cytoplasm has *^he appearance 
of a homogeneous granular substance with oil globules and the 
remnants of the extruded chromatin scattered about irregularly 
through it (Fig. 5). Shortly after the cell-division is completed 
these deeply staining granules have all disappeared. It seems 
probable that they have been consumed in some way by the 
cytoplasm which increases rapidly in bulk. 
