COHN OR MAIZE 37 



from eight in the flint to as many as 24 or more in the 

 dent corn. 



32. The kernel. — After fertilization has taken place, 

 the kernel begins to develop. At first it appears much like 

 a water blister, but after a few weeks it has greatly in- 

 creased in size and contains a milky fluid. This is called 

 the " milk " stage, and at this time it has a sweet taste, 

 due to the presence of sugar which is later changed to 

 starch. From the milk stage it gradually changes, with 

 the ripening of the plant, to the " dough " stage, and finally 

 at maturity it becomes firm and dry. An examination of the 

 mature corn kernel will show that it is made up of several 

 distinct parts. If the kernel is soaked in warm water for 

 half an hour, it can be separated into the tip cap, the 

 hull, the aleurone layer and endosperm, and the germ. The 

 tip-cap and the hull are the outside coverings of the kernel. 

 The tip-cap is located at the tip of the kernel and serves 

 to attach it to the cob and also to protect the tip end of 

 the germ. The hull is made up of three distinct thin 

 layers, which are separated only with difficulty. They 

 are composed largely of woody fiber and of gum, which 

 keeps the kernel from drying out. The hull and the tip- 

 cap taken together make up about 7 per cent of the kernel. 

 The aleurone layer, lying directly beneath the hull, is made 

 up of a single layer of thick cells, and comprises 8 to 14 

 per cent of the corn kernel. Immediately under the 

 aleurone layer lies the endosperm, which makes up about 

 70 per cent of the grain. It is composed largely of starch 

 cells, which are of two kinds, namely, the hard or horny 

 starch, and the soft or white. In some types of corn both 

 kinds are present, while in other types we find only one 

 of the two kinds. Lying at the front of the kernel, that is, 

 facing the tip of the ear, is the germ. Starting at the tip. 



