After you have selected the ear as a type which you desire, then take 

 some grains from different parts and split them open to see that the 

 grain is of proper composition and condition. Fig. 3 gives a picture 

 of the component parts of a grain of corn. 



MECHANICAL EXAMINATION OF A KERNEL OR GRAIN OF CORN. 



It consists of 9 parts, as shown in Fig. 3. 



1. Tip cap, which covers the tip or base of the kernel and comprises 

 only about 1.5 per cent of the grain. 



2. Embryo root. 



3. Tip starch. 



4. Germ. The germ occupies the central part of the kernel toward 

 the tip end. It comprises about 11 per cent of the kernel (more in 

 high-oil corn and less in low-oil corn). The germ contains from 35 

 to 40 per cent of corn oil or from 80 to 85 per cent of the total oil 

 content of the corn kernel. 



5. Emhryo stem or stalk. 



6. Horny gluten. The horny glutenous part (aleurone layer) lies 

 underneath the hull surrounding the kernel. It comprises from 8 to 

 14 per cent of the grain (being more abundant in high protein corn), 

 and it contains from 20 to 25 per cent of protein, being the richest 

 in protein of all the parts of the corn kernel. 



7. Horny starch. The horny starchy part is the chief substance in 

 the sides and back of the kernel (the germ face being considered the 

 front of the kernel). This substance comprises about 45 per cent of 

 ordinary corn, but is much more abundant in high protein corn and 

 less abundant in low protein. Although rich in starch, it contains 

 about 10 per cent of protein (more in the high protein corn and less 

 in the low protein corn) . It contains a greater total amount of protein 

 than any other part of the kernel. 



8. Corn starch. The white starchy part occupies the center of the 

 crown end of the kernel and usually partially surrounds the germ. 

 It comprises about 25 per cent of the kernel (less in high protein 

 corn and more in low protein corn). It is poor in protein (5 to 8 

 per cent). 



9. Hull. The hull is the very thin outer coat. It comprises about 

 6 per cent of the kernel and contains a lower percentage of protein 

 (about 4 per cent) than any other part of the kernel. 



When the grain sprouts, No. 2, the embryo root, goes down into the 

 ground. No. 5, embryo stem, goes upward out of the ground to make 

 the stalk. 



