Page 97 - My FlipBook

polygonal cells—many-sided cells. But around the surface of
this there is something of a membrane, a very thin mem-
brane, and it is lined with columnar cells which present a
nucleus at a certain time in their growth. Now, if we cut a
section of dry grain and undertake to make stains we will
find that the cells do not take the stains, or possibly a few
cells around the scutelum may stain. (I like to call that the
perigerm—around the germ—instead of scutelum.) A few cells
in the germ may take the stain also. But generally the cells
are thoroughly inactive, and in that condition will not take
stain at all. If, however, the grain is planted for six dr eight
hours, or better, twelve hours, we will find many of the cells
take the stain readily, and after fourteen or eighteen hours
all of the cells of the perigerm, the polygonal cells and the
epithelium-like cells, or the columnar cells around the mar-
gin, will take the stain very readily indeed ; they have become
active and the nucleus will show the stain very much more
prominently than the body of the cell. The whole of the
cellular elements of the grain in the germ, and in the peri-
germ, have waked up and have begun active functional work.
Now, by the end of twenty-four hours after planting we will
notice that the starch remains the same ; it does not take the
stain ; it is laid up in little cellular divisions that are formed
all through the pericarp, but just around the margin of the
perigerm we will notice that these have begun to become
empty, and then we will discover another thing that we were
not able to see in the germ before—that there are ducts ra-
diating from the germ all through this perigerm; they are
running in every direction through it ; they were there be-
fore, but they did not take the stain at all, and it was not
possible to differentiate them from the cellular elements.
They are very small; now they have become larger, and if
you will follow that with sugar tests you will find that those
ducts are filHng with a solution of glucose. Just as the starch
disappears from this region around the perigerm these ducts
will become filled with glucose, and with the sugar tests we
may follow the motion of the solution of the sugar from the
outer margin of the perigerm until it reaches into the germ.
Ducts that we could not discover, that did not exist, at first
in the germ open, cells that were solid and joined together
open and form tubes through which this solution of sugar

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