STRUCTURE OF SEED. 197 



not been sufficiently observed, and I ought the more to 

 abstain from mentioning them here, since they belong 

 entirely to Physiology. 



Section IV. 

 Of the Embryo. 



The Embryo is the object and end of the whole func- 

 tion of sexual reproduction. It is a young plant in 

 miniature, already provided with every organ essential 

 for nutrition, — with a root, which at this age bears the 

 name of Radicle : with a stem, which receives from 

 analogy the name of Cauliculus, or more usually that 

 of Plumule ; and lastly, with leaves themselves, to 

 which, seeing that their appearance differs much from 

 others, the name of Cotyledons has been given. Let 

 us examine the embryo at its three ages — 1st, whilst it 

 is in the state of an unfecundated germ ; 2d, during its 

 state of torpor in the fecundated seed ; and 3d, during 

 the changes it receives by the act of germination. 



The first of these articles will be short ; for the em- 

 bryo is hardly visible before fecundation : as soon as it 

 can bo perceived it appears very small, floating in the 

 water of the amnios. It is possible that the radicle 

 draws its nourishment, either from the hilum or from 

 the amnios, without having any organic connexion with 

 either, and by simple absorption, analogous to that by 

 which the roots draw the nourishing fluids from the 

 earth. It is possible that at this period of its life, the 

 extremity of the radicle communicates by a vascular 

 filament with the umbilical cord, and by this filament it 

 may receive its fecundation and nourishment; but it has 



