Fig. 228. — Hull, endosperm, and embryo. (a) The husk or skin, which 

 covers the whole grain ; it consists of two distinct layers, the outer and inner, 

 which when removed constitute the bran and contain practically all the crude 

 fibre of the whole grain, (b) A layer of gluten cells, which lies immediately un- 

 derneath the husk ; it is yellow in colour, and cannot be readily separated from the 

 remainder of the grain. This part is richer than any other in gluten, (c) The 

 embryo, which is readily distinguished by its position and form ; it also contains 

 gluten, though it is particularly rich in oil and mineral constituents, (d) The 

 endosperm portion, which is composed chiefly of starch ; the dark colour in- 

 dicates the yellow, flinty part, in which the starch-holding cells are more closely 

 compacted. (From Myrick, The Book of Corn, Orange Judd Co.) 



the ear, and practically in the middle, usually extending from 

 one-half to two-thirds of its length (Figs. 227 and 228). The 

 embryo contains all the vital parts of the young plant, as de- 

 scribed elsewhere (5 63). It varies greatly in size, comprising 



42 * 



XIII. 



CHEMICAL COMPOSITION OF MAIZE GRAIN 659 



It consists mainly of carbohydrates (94 per cent) and con- chai 

 tains nearly all of the crude fibre of the grain; it contains a 

 lower percentage of protein than any other part of the grain. 

 In the process of manufacture the hull is usually removed as a 

 by-product known as maize bran. 



614. The Embryo or " Germ".— The embryo lies at the 

 tip end of the grain, on the upper side facing toward the tip of 



