174 Gardner—Studies on Growth and Cell 
OBSERVATIONS. 
The Resting Cells—These are large and enclose a well- 
formed nucleus. The nuclear substance, or nucleoplasm is. 
stained a bluish crimson. The nuclear substance of the cells 
in the bean root contains but a very small quantity of chromatin. 
By careful focusing it is possible to distinguish minute chro- 
matin granules, stained somewhat darker than the very faint. 
linin threads. The nucleolus is a large, rounded mass, 
and stains a dense bluish black. It may be in the centre of 
the nucleus, or as is more usual, it is excentrically placed. 
Number of Nucleol.—There may be one nucleolus present, 
or more than one. The usual number in cells in the growing 
apex is one, in cells back of the apex, it is as common a 
feature to have two, as it is to have one. Very rarely are 
three large nucleoli to be found. Frequently, in nuclei with 
one or two large nucleoli, many small nucleolar fragments 
are found. These smaller pieces are always recognizable as. 
nucleolar material by their density and staining relations. 
DIvISION. 
The first traces of division are to be seen in an aggrega-. 
tion of the nuclear material (Plate XVIII, Fig 6.). This 
aggregation always occurs previous to the formation of 
the spirem thread. The minute chromatin granules becom- 
ing more massed together appear darker than in the resting 
cell. The aggregation continues and the entire nuclear sub- 
stance appears darker, due to massing together in small quan- 
tities of its contents (Fig. 5). These small thread-like masses. 
soon fuse into an almgst continuous thin thread. During this 
process the nucleolus retains its color relations, and as the 
aggregation of the nuclear substance and the formation of 
the thread occur, the nucleolus comes to lie in more and more. 
intimate relation with these. The nucleolus is related to the 
nuclear reticulum in such a way that the fibers penetrate its 
