The Seed and its Germination. 
507 
If the seed be watched during germination, it is found that 
in its cells other changes go on besides this preliminary one. 
After about five days of development the young embryo has 
attained considerable size, its primary root protruding for about 
two inches, and bearing a number of secondary rootlets of 
variable length. The cotyledons of the seed remain inside the 
endosperm, which has become swollen, and contains a quantity 
of water. It is through the cotyledons that the food material is 
absorbed. The endosperm contains at this period a certain 
quantity of the unaltered oil, some fatty acid, another acid 
which can be separated out by soaking it in water, and which 
is then capable of crystallising ; also a quantity of sugar. Of 
these, the sugar and the new acid body are the only ones which 
can be absorbed by the process of diffusion. At a still later 
period, when the reserve materials of the endosperm are almost 
exhausted, the only constituents left in the cells are thecrys- 
tallisable acid and the sugar. It is evident, therefore, that 
besides the decomposition of the oil into fatty acid and glycerine, 
further splitting up leads to the transformation of these into the 
newly appearing bodies mentioned. The glycerine resulting 
from the first action is changed almost immediately it is formed, 
no observers having been able, indeed, to prove its presence in 
the cells in a free state. From many considerations, which need 
not be entered into here, it is inferred that it is the source of 
the sugar which is found. Glycerine has been ascertained by 
Messrs. Brown and Morris to be capable of nourishing isolated 
embryos of barley almost as well as solutions of sugar itself. 
The fatty acid, again, which disappears from the endosperm as 
the germination advances, gives rise to the other form of acid, 
which is found to be capable of dialysing. Both these, i.e. the 
sugar and the new acid, can be traced into the young plant. 
There is no ferment present which can produce these later 
transformations. A very curious fact is, however, noticeable, 
which shows how the changes can take place. The endosperm 
of the castor-oil plfnt retains a power which that of the barley 
does not. It is capable of a certain amount of development and 
growth apart from the presence of the embryo. In the barley 
this power is quite absent — the endosperm does not change at 
all if the embryo be dissected out. This capability of indepen- 
dent growth in the castor-oil endosperm indicates a certain 
amount of life dormant in the cells. In all seeds the endo- 
sperms have at first been living, and evidence of their life has 
been afforded by the deposition of the reserve materials in their 
cells, for each cell regulates its own internal concerns. In the 
young seed before maturity we have a living embryo surrounded 
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