28 GERMINATION OF THE SEED. CHAP. I. 



passes through the cotyledons, or is contained in 

 them ; because the embryo dies when they are pre- 

 maturely cut off. But the farinaceous substance of 

 the cotyledons, at least in exalbuminous seeds, is a 

 proof that they themselves contain the nutriment. 

 They are to be regarded therefore as repositories of 

 the food destined for the support of the embryo in 

 its germinating state. And if the seed is furnished 

 with a distinct and separate albumen, then is the 

 albumen to be regarded as the repository of food, 

 and the cotyledon or cotyledons as its channel of 

 conveyance. But the food thus contained in the 

 albumen or cotyledons is not yet fitted for the 

 immediate nourishment of the embryo. Some pre- 

 vious preparation is necessary ; some change must 

 be effected in its properties. And this change is 

 effected by the intervention of chemical agency. 

 "Action of It has been shown in the foregoing section that a 

 inoisture. see( ^ is no sooner placed in the earth than it begins 

 to imbibe moisture. But the moisture thus im- 

 bibed isjmnrellTately absorbed by the cotyledons or 

 albumen, which it readily penetrates, and on which 

 it immediately begins to operate a chemical change, 

 dissolving part of their farina, or mixing with their 

 oily particles and forming a sort of emulsive juice; 

 the consequence of which change is a slight degree 

 of fermentation, induced, perhaps, by the mixture of 

 the starch and gluten of the cotyledons in the water 

 which they have absorbed, and indicated by the 

 extraction of a quantity of carbonic acid gas as well 

 i 



