492 
MONTGOMERY. 
[Vol. XV. 
it does not appear to contain vacuoles. The nucleus itself is 
somewhat elongate and irregular in outline, and, owing to its 
maximum degree of contraction (a characteristic of the end of 
the metaphase), its chromatin builds a dense network within it. 
A study of the cell body at this stage allows us to follow 
the morphological changes undergone by those nucleoli which 
had been discharged by the nucleus (Figs. 198-203). The 
cytoplasm gradually assumes a reticulate or a somewhat granu¬ 
lar structure, and finally a most regular vacuolar or alveolar 
structure. As the cell body decreases in size the discharged 
nucleoli lying in it gradually stain less deeply, they lose their 
rod-like form, and no longer remain isolated, but all the nucleo¬ 
lar substance in the cytoplasm gradually becomes confluent, 
and becomes arranged in the form of a coarse, irregular network 
of substance distributed in the cytoplasm, and readily distin¬ 
guishable from the latter by its different staining properties 
(Figs. 201-203). By a hasty inspection this network of nucle¬ 
olar substance might appear to represent branches' of the 
nucleus, but a careful study shows that at this period of its 
growth the nucleus has no branches. As the cell continues to 
become smaller the amount of nucleolar substance in the cyto¬ 
plasm gradually becomes less and less, first the network at the 
periphery of the cell disappearing, then that in the vicinity of 
the nucleus, until at the conclusion of the metaphase no nucle¬ 
olar substance is any longer to be seen in the cytoplasm. I am 
unable to determine whether it is finally discharged through 
the cell membrane or whether it becomes metamorphosed into 
cytoplasm ; it certainly is not excreted through the cell duct, 
since no nuclear substance occurs in the latter, and at this 
stage the duct is no longer an open tube, but all the secretion 
corpuscles having been expelled from it, it is again filled with 
cytoplasm. The suggestion may be made that at least a portion 
of this nucleolar substance remains in the cytoplasm, so that in 
the succeeding prophase the nucleolus within the nucleus might 
find the material necessary for its growth in the nucleolar sub¬ 
stance suspended in the cytoplasm ; thus there might be, in the 
history of the nucleolar substance, periods of its expedition into 
the cytoplasm alternating with those when it is again taken 
