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Beer. — Studies in Spore Development. III. 
the meshes of the network, here and there, so as to bring the two sides of 
the mesh closer together. When these two sides of the stretched mesh 
happen to contain chromatic thickenings upon them these will naturally 
form, in such cases, a parallel pair. 
The degree of coarseness of the nuclear reticulum is also, no doubt, to 
some extent influenced by the penetration and action of the fixative. 
At the same time, in the majority of cases, the coarser reticulum evidently 
denotes a nucleus which has not passed into such a complete condition of 
rest as the one enclosing the finer and more even network. It is possible 
that the coarser reticulum may always become more evenly distributed 
before the next division is entered upon, but it appears more probable that 
the nuclear condition in rest depends upon the rapidity with which the 
divisions are following one another. 
The nucleoli are numerous in these resting nuclei. Three to six — or 
even more— nucleoli occur in each nucleus, and several of these can often be 
seen to be elongated, vermiform, or hour-glass shaped (PL LII, Fig. 16). The 
reticulum is usually contracted away from the nucleoli so as to leave a clear 
space round each of them. The nucleoli do not stain deeply, but colour as 
plasmosomes. 
When a resting nucleus, such as that described above, is about to enter 
upon a mitotic division we find that certain of the arms and anastomoses 
of the network are withdrawn so that the meshes of the reticulum become 
larger and more open. This withdrawal of the cross connexions takes place 
along certain lines, so that there is a tendency manifested for lengths of 
filament, uninterrupted by anastomotic communications, to differentiate out 
of the network. At the same time the filaments of this looser and more 
open reticulum become thicker and more deeply stained with dyes. The 
nucleoli still continue to be large, numerous, and plasmatic in their standing 
reactions (Fig. 2). 
The continued retraction of the branches and anastomotic connexions 
gradually leads to the formation of a spireme in which the filaments are 
smooth and stain fairly deeply in haematoxylin, gentian violet, &c. Quite 
early in its differentiation the spireme often shows a distinction of 
more darkly stained (chromatin) granules embedded in a lighter (linin) 
thread, but in my preparations of older stages I have failed to see this 
appearance. 
The filaments which have arisen from a stage such as I have drawn in 
Fig. 2 by the further withdrawal of the branches of the reticulum, are still 
comparatively straight and show a certain amount of polarization (Fig. 3). 
This polarization of the filaments as they become differentiated out of the 
reticulum recalls the arrangement of the chromosomes during the telophase 
of the preceding division. It is not improbable, therefore, that the chromo- 
somes which emerge at the prophase of a division may roughly occupy the 
