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40 SPERMATOGENESIS AND FECUNDATION OF ZAMIA. 
stained sections, and the writer can hardly believe it to be due to con- 
traction caused by reagents, as might be supposed. Indeed, the phe- 
nomena shown in Zama would appear to demonstrate clearly that it is 
of normal occurrence here; for, as shown later, after this collection of 
the stainable granules in one portion of the nucleus, the other portion 
of the nucleus remains occupied by a plain reticulum of unstainable 
matter filled with minute refractive granules. Sargent (96) was able 
to observe this stage in living nuclei of the pollen grains of Zzliiun 
martagon, showing that in that instance the apparent contraction phe- 
nomenon was evidently a normal one. No conclusive evidence has 
been obtained, however, which shows its significance in the process of 
division. In the central cell of Zama it is only occasionally that 
nuclei can be found in this condition, and it is not a favorable place to 
study the phenomenon. ‘The collection of deeply staining granules in 
irregular masses would seem to be immediately followed by their 
gradually moving toward one side of the nucleus and collecting around 
the nucleolus. The nucleolus is always in the midst of the mass of 
granules after the completion of the contraction, and it may be that 
the contraction is always toward that side of the nucleus to which the 
nucleolus lies nearest. The conviction can hardly be avoided that the 
nucleolus must be connected in some important way with the coijlee- 
tion of these granules around it. In Zama the early stages at least of 
this phenomenon would seem not to be a contraction, but rather a move- 
ment of the stainable elements, granules, ete., of the nucleus to a 
region in close proximity to the nucleolus, while a colorless, slightly 
granular, nonstainable matter remains in the original position. This 
unstained plasma is clearly visible and unmistakable and retains the 
original reticular structure (fig. 30). It might at first be assumed that 
this colorless network was due to the albumen used in attaching the 
sections, or to some deposit from the paraffin or killing reagents. 
Such could not be the case, however, as in some places where the 
nuclear membrane had become contracted away from the cytoplasm 
no such structure intervened, which would have been the case had it 
been caused by the albumen cement or any of the other reagents used 
in the process of killing, imbedding, etc. By a careful examination 
of the edges of the dense mass of granules occasionally a place may be 
observed where a few of the stainable granules may be found extend- 
ing out into a strand of this unstainable matter (fig. 30). It would 
seem from this that the chromatin granules follow along the reticulum 
of this hyaline plasm in the process of collecting in the synapsis stage, 
and that in such cases as the above a few isolated chromatin granules 
had not yet united with the general mass when the material from 
which the section was taken was killed and fixed. The reticulum of 
this colorless plasm seems thus to be coextensive with the reticulum of 
the densely staining portions of the nucleus, and apparently occupies 
