CHAPTER XV 



COMPOSITION AND FEEDING VALUE OF 



CORN 



THE GRAIN AND BY-PRODUCTS 



PHYSICAL STRUCTURE* Dr. C. G. Hopkins, of the Illinois 

 Experiment Station, has made a very satisfactory mechanical analysis 

 of the corn kernel. He divides it into six different parts, as follows : 



1. Tip Cap. This is a small cap covering the tip end of the 

 kernel and servmg as a protection to the end of the germ. It consists 

 of material somewhat resembling the cob. Occasionally in shelling 

 corn the tip cap remains attached to the cob, leaving the tip end of 

 the germ uncovered, but nearly always sticks to the kernel. 



2. Hull. This is a very thin outer covering of the kernel. It 

 consists largely of carbohydrates, especially fiber or cellulose, although 

 it also contains a small percentage of other constituents. 



3. Horny Glutenous Part. This part lies immediately underneath 

 the hull. It constitutes a second covering of the kernel. For short 

 it is called "horny gluten," although it is, of course, not pure gluten. 

 However, it is the richest in protein of any part of the corn kernel. 



4. Horny Starchy Part. This part lies next to the horny gluten, 

 on the back and sides of the kernel. For short it is called "horny 

 starch," although it is not pure starch, as it contains considerable 

 amounts of other constituents, especially protein. In an examination 

 of the kernel with the unaided eye, the horny glutenous and the horny 

 itarchy parts are not readily distinguished from each other, the line 

 between them being somewhat indefinite and indistinct. Considered 

 both together, these two parts constitute the horny part of the kernel. 



5. White Starchy Part. This part occupies the crown end of 

 the kernel above the germ, and it also nearly surrounds the germ to 

 ward the tip end of the kernel. For convenience, this material is 

 called "white starch," although it is not pure starch. In some kernels 

 the horny starch extends nearly or quite to the germ, near the middle 



'Bulletin No. 87, Illluois Experiment Station. 



