Ser, ME à MUMBILICAE VESSELS, ds

times, 1 fuppofe, before its nativity, as the chick perforates the air- bag, and is heard to chirp, before it is excluded from the fhell.

Hence it would appear, that both the artery attending the feminal roots above mentioned, and this artery on the chorion of the chick, muft perform fome more important office than to fupply nourifhment to the coats of the abforhbent veflels, which imbibe the mucilage of the feed, or the white of the ego, and which abforbents muft them- felves poñlefs their proper vafa vaforum. And what more important office can they have than that of oxygenating the blood of the vese- table or animal embryon? And this becomes more probable as they both perifh at its nativity like the placenta and cetyledons of vivi- parous animals.

$. As the incubation of the chick advances, it differs from the feed- embryon in the produétion of inteftines, with a ftomach, on the in- ternal furfaces of which the mouths of the abforbents now terminate; and laftly in the production of a mouth and throat to receive and fwallow the remainder of the albumen, in which it fwims; whereas the feed-embryon fhoots down new roots into the earth with an ab- {orbent fyftem to acquire its nutriment, as that from the cotyledons of the feed becomes exhaufted. See Set. VII. 1, 2.

Nor is there any thing fimilar to the yolk of the ess found in the feeds of vegetables, which is drawn up into the inteftines of the young chick about the time of its exclufion from the fhell to ferve it with nutriment for a day or two, tillit can learn of its parent by imitation to feleét and fwallow its adapted food. Nor is the fetus of vivipar- ous animals furnifhed with any thing fimilar to the yolk of oviparous ones, as they have milk ready prepared for their firft nutriment in the breaît of the mother.

As foon as the new foliage of the plant rifing out of the ground becomes expanded, and the root defcending penetrates the earth with its fibrous ramifications, the umbilical fyftems of veflels ceafe to aét, both the abforbents, which previoufly fupplied the young embryon

E with