CONCENTRATED FOODS 265 



proper, apart from the husk, but little useless material fibre, 

 silica, etc. is found, and the proportion of water is necessarily 

 small. Such material is, therefore, eminently suitable for the 

 nutrition of animals. 



All the materials mentioned above are, as they exist in 

 seeds, insoluble in water. They could not, therefore, be 

 transferred to the growing points, and the seeds would be 

 incapable of germination, if it were not that they also contain 

 enzymes capable of resolving the substances into soluble 

 compounds. When germination takes place, the seeds absorb 

 large quantities of water and oxygen gas ; carbon dioxide is 

 evolved, proteins are resolved to amides and starch into 

 sugars. Fats also are acted upon by lipolytic ferments. The 

 products of these changes are transferred to the points of 

 growth, and the rootlets and shootlets are formed. Seeds 

 which have sprouted, i.e. germinated, are, therefore,- of lower 

 nutritive value ; and when the process is complete, the seeds 

 are entirely exhausted. The young sprouts formed from the 

 material of the seed are, however, highly nutritious. 



As seeds are enclosed in a fruit or protective covering 

 of some kind, they are less subject to the attacks of fungoid 

 parasites than the stems and leaves. They contain a large 

 amount of nourishment in small bulk, and if kept dry they 

 remain unchanged for years. The nutrients are readily 

 digestible, and the ratio of dynamic to thermic energy is 

 therefore high. 



The chemical composition of seeds is more constant than 

 that of the vegetative organs, and is fairly characteristic 

 of the kind of plant. The influence of climate and season, 

 soil, manuring, etc., on the composition of seeds is compara- 

 tively small ; it may be attributed almost entirely to the effect 

 on the ripeness or maturity of the seed. 



Imperfect ripening, to whatever cause it may be due, 

 inevitably results, in the case of cereals, in deficiency of 

 starch. Under these conditions the grain contains a larger 

 percentage of nitrogenous matter, but a considerable pro- 

 portion of it is not properly elaborated as protein ; the 

 amount of amides is, therefore, abnormally large. 



