The analogy between seeds and eggs has long been observed, and is confirmed by the mode of their production. The egg is known to be formed within the hen long before its impregnation; C.F. Wolf asserts that the yolk of the egg is nourished by the vessels of the mother, and that it has from those its arterial and venous branches, but that after impregnation these vessels gradually become impervious and obliterated, and that new ones are produced from the fetus and dispersed into the yolk. Haller's Physiolog. Tom. VIII. p. 94. The young seed after fecundation, I suppose, is nourished in a similar manner from the gelatinous liquor, which is previously deposited for that purpose; the uterus of the plant producing or secreting it into a reservoir or amnios in which the embryon is lodged, and that the young embryon is furnished with vessels to absorb a part of it, as in the very early embryon in the animal uterus. The spawn of frogs and of fish is delivered from the female before its impregnation. M. Bonnet says that the male salamander darts his semen into the water, where it forms a little whitish cloud which is afterwards received by the swoln anus of the female, and she is fecundated.--He adds that marine plants approach near to these animals, as the male does not project a fine powder but a liquor which in like manner forms a little cloud in the water.--And further adds, who knows but the powder of the stamina of certain plants may not make some impression on certain germs belonging to the animal kingdom! Letter XLIII. to Spalanzani, Oevres Philos.