20 A STUDY OF WHEAT. 



bright yellow. Nitrogen is found only in cell-contents, and is 

 never found in cell-walls. 



8. Inside of the layer of albumen is found only one struc- 

 ture until we reach the embryo, at the base of the grain. It 

 is composed of large, thin-walled hexagonal cells, loaded with 

 starch, see Fig. 2. To see these cells plainly under the mi- 

 croscope a very thin section must be cut from the central part 

 of the grain with a razor, or a sharp knife, and then washed 

 off carefully with a camels-hair brush, so as to remove the 



Fig. i. Outer Layer of Albumen. X 200. 



grains of starch, when we find a delicate white structure re- 

 sembling a honey-comb in all except color. At the center of 

 the grain the cells are the largest, and are quite uniform in 

 shape and size, measuring nearly i-io of a millimeter (1-250 

 of an inch) in diameter. At the surface of the albumen the 

 cells are quite long and narrow, and lying in such a way that 

 they appear to radiate from the center toward the surface. 

 The walls are delicate and nearly transparent, showing under 

 a high magnifying power the different structures or layers of 

 cellulose. The cells are loaded with starch grains, as seen at 

 #, Fig. 2. 



9. Just inside the hexagonal cells, which fill the inside of 

 the grain, and at the same time surrounding the embryo, is 

 found a single row of empty compressed cells, quite difficult 

 to demonstrate. 



10. The embryo occupies the lower end of the grain, and 

 is a small oval body about one millimeter in width and two 

 in length. The main object in life for the wheat is the pro- 

 duction of this embryo. The development of the stem, the 

 branching and expanding of the leaves, the whole life and his- 



