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Transactions of the Society. 
cells of the worm, Piscicola. In these cells a very large number 
of nucleoli are developed. Then at the time when the cell begins 
its secretive activity by the formation of granules in the cyto- 
plasm, the nucleus, which up till now has been much lobulated, 
becomes rounded and contracts. The result is that the nucleolar 
fragments become shot out into the cytoplasm, where they form 
a kind of reticulum which persists for some time. Later it 
disappears, its ultimate fate being unknown. 
Extrusions of nucleolar fragments from “ resting cells ” have 
been described by Walker and Tozer (59) in quite a number of 
animals, and some plants. They found this process occurred in 
Spongilla , Planaria lactea , Polycelis nigra , leucocytes from the 
small intestine and cells from both the small and large intestines 
of the rabbit, and in cells of the leech (Clepsine), in endoderm 
cell of Hydra fusca, and in the root tip of the bean. An earlier 
paper by Walker and Embleton (58) was devoted to an account of 
the process in the endoderm cells of Hydra. They noted that 
while the extrusion of nucleoli in the endoderm cells was very 
common, in the ectoderm cells it was remarkably rare. As the 
endoderm cells are actively engaged in digestion, the conclusion 
was drawn that the process was related to digestion. In both of 
these papers the writers emphasize the fact that the nucleolar 
substance which has been thrown out into the cytoplasm under- 
goes a change in staining reaction. Walker and Tozer conclude 
that the phenomena of nucleolar extrusion “ occurs in somatic 
cells of both animals and plants very generally, particularly in 
those cells where active metabolism takes place, and multiplica- 
tion does not occur to any great extent, or is practically absent in 
the adult organism.” The process is interpreted “as being directly 
connected with nuclear metabolism, and the migrating nucleoli 
are looked upon as the bearers of excretory and secretory products 
from the nucleus to the cytoplasm.” This may be the means by 
which the nucleus discharges material when the cell is in the 
vegetative condition. 
In the nerve cells of mammals, Page May and Walker (Jfi) 
have described another type of nucleolar behaviour. Their material 
consisted of the cells from the Gasserian and cerebrospinal ganglia 
of rats, rabbits, cats and monkeys. The nucleoli in these cells 
increased in number by budding or fission ; then particles were 
extruded from the nucleus, and these, after undergoing a change 
of staining reaction, were in some cases discharged completely 
from the nerve cell into the cytoplasm of a leucocyte or of a 
capsular cell. 
Another worker who has described nucleolar extrusion is 
Nakahara. He has observed the process in the adipose cells and 
in the silk-gland cells of certain insects. In the former case he be- 
lieves that the extruded nucleolar fragments become metamorphosed 
