FEEDS AND FEEDING 329 



Carbohydrates. Plant fiber, sugar and starch are the 

 most important of the carbohydrates. They are of about 

 the same composition, containing carbon, hydrogen, and 

 oxygen only, no nitrogen being present. 



The cell wall or structural part of a plant is called cellulose. 

 Where great strength is needed, the cell walls become thick 

 and hard as in trees. There is little cellulose in seeds. It 

 is found in greater proportions in ripe hay, straw, and corn 

 fodder. Paper is now chiefly made from the cellulose or 

 fiber of wood. Flax fiber and cotton are good examples of 

 nearly pure cellulose. Pure fiber has very little color, odor, 

 or taste. 



EXERCISE. Cellulose. Make wet paper balls of as many 

 different kinds of paper as you have in school. The water 

 will remove starch and other substances and leave the pure 

 fiber or cellulose. Brown paste-board may be used to illus- 

 trate the fiber in straw of small grains. Fiber of flax is 

 found in linen paper and linen cloth. Most soft white 

 paper is made of wood fiber. 



Starch is stored by nearly all kinds of plants. It is a very 

 abundant substance. Small grains, corn, and the dry matter 

 of root crops are especially rich in this substance. Potatoes 

 and corn furnish most of the pure starch in the commerce 

 of America. Because of its abundance and ease of digestion, 

 starch is one of the most important feeds. It is readily 

 converted into glucose, or grape sugar, by treatment with 

 acids. The glucose syrups are largely derived from the 

 starch of corn. 



EXERCISE. Showing Starch. Cut open kernels of corn, 

 wheat, rye, and other common grains. Examine the white- 

 powder. This is nearly pure starch. 



Sugars are closely related to starch. There are three 

 kinds: cane sugar, milk sugar, and grape or fruit sugar. 

 These are very much alike in composition. All resemble each 

 other in their properties. Cane sugar is the common sugar 



