THE SEED 69 



suggest that during germination oil is decomposed into 

 its constituents, acid and glycerine, likewise by means of 

 a ferment. Moreover, it is well known that fatty acid 

 when set free furthers the breaking-up of oil in water 

 into very fine drops with the formation of so-called 

 emulsions, such as the white oily liquids we call ' milk ' 

 cow's milk, coconut-milk, and so on. This formation 

 of emulsions plays a great part in the nutrition of an 

 animal's organism ; very likely it also plays a certain 

 part in the nutrition of the embryos of oily seeds. 



The first stage in the nutrition of a young seedling has 

 now been explained. By the action of water and 

 ferments the immobile material stored up within the 

 seed is brought into circulation, and becomes available 

 to the seedling. We can easily prove that the develop- 

 ment of the embryo takes place at the expense of the 

 stored material. We have only to cut off the cotyledons 

 of a leguminous plant to stop the further development 

 of the embryo, even though its root and stem have 

 already attained to some degree of development. The 

 cessation of further growth in the embryo cannot be 

 explained by the fact of its having been wounded ; 

 on the contrary, experiments prove that it has still 

 considerable vitality. We can cut it in pieces, in 

 various ways, and each segment will develop if only a 

 connection with the cotyledons containing the food-store 

 be maintained. In fact, if we cut off the rootlet, leaving 

 the plumule connected with the cotyledons, the stem 

 will develop even more quickly than if it had been 

 attached to an uninjured embryo ; and, vice versd, if 

 we cut off the plumule, leaving the rootlet connected with 

 the cotyledons, the rootlet will develop more strongly 

 than if it had been attached to an uninjured embryo. 

 In these cases one of the two organs evidently uses the 

 food stored up for both. In seeds with endosperm 

 (albuminous seeds) the embryo is not organically 

 connected with the source of its food supply ; it may 



