GERMINATION OP THE SEED. 
1-25 
embryo during its germination, as do the cotyledons of dicoty- 
ledonous plants. In some monocotyledons is perceived under 
the albumen or white, a part called Vitellus , or the yolk ; this 
like the albumen is entirely converted into nourishment for the 
young plant ; it may be seen in the seeds of grasses, and is con- 
spicuous in the Indian corn. 
We have observed that moisture is essential to the germina- 
tion of the seed. Earth , though not absolutely essential, is use- 
ful, as affording to the vegetable egg a favorable situation, where 
it may receive the influence of the various agents, which are 
to perform their offices in the developement of its parts. 
It seems too, not improbable, that some of the constituent ele- 
ments of earth may be absorbed by the germinating plant, and 
converted into nourishment. It is however sufficiently apparent 
that plants may vegetate without earth. The parasite grows 
upon the bark of other plants ; many seeds vegetate in water, 
and some if moistened and placed on cotton, or other supporting 
substance. Air is essential to vegetation ; under an exhausted 
receiver a seed will,not germinate, although possessing every 
other requisite. Seeds that are planted very deeply in the 
ground, do not vegetate, unless accidentally ploughed up, or ex- 
posed to the contact of the atmosphere. Acorns which are sup- 
posed to have lain for centuries, have germinated as soon as 
they were raised sufficiently near the surface to receive the in- 
fluence of air. You will recollect that in the process of germi- 
nation, oxygen gas unites with the carbon of the seed, and car- 
ries it off in the form of carbonic acid. Air furnishes that im- 
portant agent, oxygen, which is the first moving principle of 
vitality. Carbon constitutes the greater part of the substance 
of seeds ; and this principle being in its nature, opposed to pu- 
trefaction, prevents seeds from rotting, previous to their being 
sown. Some seeds having an abundance of carbon, are capable 
of being preserved for ages ; while others, in which this ele- 
ment exists but in a small proportion, require to be sown almost 
as soon as ripe ; and such as are still more deficient in carbon, 
lose their vital principle, before separating from the pericarp. 
You can now understand that oxygen is important to germi- 
nation, on account of its agency in removing the carbon which 
held the living principle of the seed in bondage. 
The absence of light is favorable to the germination of seeds ; 
for light acts upon plants in such a manner as to take away ox- 
Nourishment of the young plant — Various agents promote the germina- 
tion of the seed — Air essential to vegetation — Oxygen an important agent 
—Carbon in relation to seeds — The absence of light favorable to the ger- 
mination of plants. 
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