Igo BOTANICAL GAZETTE [MARCH 
cate that chromatin, linin, and nucleoli are of the same substance, 
the form and amount of which vary as the nucleus is quiescent 
or actively dividing. If then the nucleoli of the higher plants 
are not genetically derived from the chromatic substance, but, as 
Strasburger holds, come from the degeneration of the mantle 
fibers, then the function and mode of origin of these nucleoli 
must have undergone a radical change in the course of evolu- 
tion. Strasburger attributes this difference in the function of the 
nucleoli in the higher plants from that found in lower forms to 
the absence of centrosomes. 
The view expressed in this investigation that the nucleoli are 
accumulations resulting from the quantitative reduction of the 
chromatin is not only in harmony with the evidence derived 
from lower forms, but better explains the conditions observable 
in the plerome cells which have no use for -material with which 
to manufacture achromatic figures. 
THE CHROMATIC FIGURE. 
The chromatic granules of meristematic cells that are in a 
quiescent state are distributed in the linin network, but lie at the 
periphery of the nucleus rather than uniformly distributed, while- 
the linin strands can be seen anastomosing with the more cen- 
trally lying nucleoli. In these nuclei the granules appear so 
minute even with the one-twelfth inch homogeneous immersion 
that no satisfactory evidence was obtained as to whether they 
have a definite arrangement. That they do not always appear to 
be of equal size can be seen by inspecting the lower right-hand 
cell shown in fig. z. This variation may be only apparent, due 
possibly to inequalities of fixation or staining, or in some cases 
to an optical appearance produced by looking upon several 
granules overlying one another in the successively superimposed 
strands of the network. In cells, however, where the beginning 
of the enlargement of the nucleus indicates an approaching divi- 
sion, the network appears to consist of strands each of which is 
double; the granules that lie opposite each other in each of the 
halves of the strand are connected by cross bridges of linin. 
Fig. 2 shows a cell cut crosswise, in which appear the first indi- 
cations of the double nature of the strands of this network. 
