1904] MERRIMAN: VEGETATIVE CELL DIVISION 197 
represent sections of a cell, one drawn at high, the other at low, 
focus, so as to allow a complete reconstruction of the chromatic 
figure. At the right-hand upper pole of fig. gg it can be seen 
that one chromosome cut in cross section reveals the tetrad | 
structure. The chromosomes can be seen now to have become 
more vacuolated. The adjacent chromosomes are being drawn 
together by the linin substance, which is more deéply stainable 
than the remains of the spindle fibers. A reconstruction of the 
sections of the cell indicate that in the fundament of the daughter 
nuclei a more or less continuous spireme coil is being formed. 
An opaque diffusible substance slightly stained by haema- 
toxylin and other nuclear stains can be discovered between the 
chromosome coils. It appears to become denser as the vacuole- 
like spaces in the chromosomes increase in number (compare 
figs. 42-46). This substance has not before been recognizable. 
The chromosomes as they pass to the poles lie in a perfectly 
clear field, and it is not until they begin to fuse to form the 
Spireme that this substance makes its appearance. — 
There is not a true vacuolization of the chromosomes, since 
the spaces are defined in too regular a fashion. This regular 
formation of the vacuoles in the rings is well illustrated in fig. 46. 
What we actually have is a resolution of the chromosomes into 
the component tetrads, with a gradual decrease in size of the 
chromatin bodies, apparently accompanied by an increase in 
volume of the linin. The loss of material accompanying the 
reduction in the size of the chromatin bodies is correlated with 
the increase of the linin and also with the presence of the diffu- 
sible substance which is deposited within the coils. In Sig. 47) 4 
longitudinal section of a periblem cell, are shown the first indi- 
cations of a discrete body which can be termed a nucleolus. In 
fig. 48, where there is a continuous spireme, this is seen to lie 
Within the coils and to occupy the same central position that the 
nucleoli of the quiescent nucleus hold after the nuclear membrane 
is completed. This nucleolus is only a condensation of the 
Opaque substance to be seen in earlier stages between the chromo- 
somes. In my opinion, it owes its origin to the chromatic - 
bodies, being but a waste product of their activity. 
