NoTE XXXVII. VEGETABLE IMPREGNATION. 459

yolk ofthe egg is nouriſhed by the veſlels 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 pro- duced from the foetus and diſperſed into the yolk. Hlal- ler's Phyſiolog. Tom. VIII p. 94. The young ſeed after fecundation, 1 ſuppoſe, 13 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 em- bryon is lodged, and the young embryon 1s furniihed with veſſels to abſorb a part of it, as in the very early em- bryon 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 whitifh cloud which is afterwards received by the ſwoln anus of the female, and[ſhe 1s fecundated,.--- He adds that marine plants approach near to theſe ani- mals, as the male does not projet 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 make ſome Impreſion on certain germs belonging to the animal Kingdom! Letter XLIII. to Spallanzani, Oeuvres Philoſ.

Spallanzani found that the ſeminal fuid of frogs and dogs even when diluted with much water retained its pro- lific quality. Whether this quality be imply a fimulus exciting the egg into animal action, wnaich may be called a vivifying principle, or whether part of it be actually