^6 THEPHILOSOPHY 



Moifture, warmth, and foil, or fome fimllar matrix, are neceflary 

 for the exclufion of the young plant. This analogy has been ex- 

 tended much farther by Linnaeus, and other fupporters of the fex- 

 ual fyftem of plants. They maintain, that impregnation is equally 

 indifpenfable to the vegetation of the feed, as to the fertility of the 

 egg. But, as this doiSrine will be difcuffed when we come to treat 

 of fexes in general, we Ihall here difmifs it without farther remark. 



Eggs are not only analogous to feeds, in their general deftination 

 of reproducing individuals, and continuing the fpecles, but there is 

 a great fimilarity in the ftrufture and ufes of their refpeSivc organs. 



The internal parts of the egg are covered with a cruft or fhell, 

 and two membranes. Befide thefe, the yoke is included in a fe- 

 parate membrane. When the two firft membranes are removed, 

 the white appears every way invefting the yoke. In the white, or 

 rather on the membrane of the yoke, a fmall cicatrice is difcernible, 

 in the centre of which is the punnum /aliens, or embryo of the fu- 

 ture animal. After two or three days incubation, this punnum fa- 

 liens becomes red, and fhoots out blood- veflels, v;hich are difperfed 

 through the yoke, in the fame manner as the veflels of a foetus arc 

 diftributed over the placenta. 



A feed is likewife covered with a {hell, or cruftaceous membrane. 

 Another membrane invefts the whole kernel, or pulpy lobes of the 

 feed. Each lobe, like the yoke of the egg, is involved in a feparate 

 membrane. In every feed there is alfo a fmall cicatrice, or aperture, 

 through which the young plant iifues. Immediately under this ci- 

 catrice, the plume, or future plant, is difcernible, refembling the 

 punBum /aliens of the egg. The branches of the radicle proceed 

 from this plume, and are difperfed through the fubftance of the 

 lobes, in the fame manner as the blood-veflels iflue from the punc- 



tum 



