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of the chick like the placental vessels of the foetus of viviparous animals; or 
sometimes, I suppose, before its nativity, as the chick perforates the air-bag; 
and is heard to chirp, before it is excluded from the sheik 
Hence it would appear, that both the artery attending the seminal roots 
above mentioned, and this artery on the chorion of the chick, must perform 
some more important office than to supply nourishment to the coats of the 
absorbent vessels, which imbibe the mucilage of the seed, or the white of 
the egg, and which absorbents must themselves possess their proper vasa 
vasorum. And what more important office can they have than that of oxy¬ 
genating the blood of the vegetable or animal embryo? And this becomes 
more probable as they both perish at its nativity like the placenta and coty¬ 
ledons of viviparous animals. 
As the incubation of the chick advances, it differs from the seed- 
embryo in the production of intestines, with a stomach, on the internal 
surfaces of which the mouths of the absorbents now terminate; and lastly, 
in the production of a mouth and throat to receive and swallow the re¬ 
mainder of the albumen, in which it swims; whereas the seed-embryo 
shoots down new roots into the earth with an absorbent system to acquire 
its nutriment, as that from the cotyledons of the seed becomes exhausted. 
Nor is there any thing similar to the yolk of the egg found in the seeds 
of vegetables, which is drawn up into the intestines of the young chick 
about the time of its exclusion from the shell to serve it with nutriment for 
a day or two, till it can learn of its parent by imitation to select and swallow 
its adapted food. Nor is the foetus of viviparous animals furnished with 
any thing similar to the yolk of oviparous ones, as they have milk ready 
prepared for their first nutriment in the breast of the mother. 
As soon as the new foliage of the plant rising out of the ground be¬ 
comes expanded, and the root descending penetrates the earth with its 
ramifications, the umbilical systems of vessels cease to act, both the ab¬ 
sorbents, which previously supplied the young embryo with nutriment 
from tne cotyledons, and also the placental artery, which was spread on the 
exterior membrane of the cotyledons for the purpose of oxygenation. These 
vessels now either coalesce and decay beneath the soil, or wither and fall 
off, when raised above it in the form of seed-leaves. 
The seeds of plants are thus a sexual or amatorial progeny, produced 
principally by the male part of the flower, and received into a proper nidus, 
and supplied with nutriment by the female part of it. 
