108 THE PRINCIPLES OF AGRICULTURE 



breaks ; by supplying shade ; by contributing 

 to the beauty and variety of the landscape. 



4. The Plant in its Relation to Animal Life 



174. Nearly all domestic animals live directly 

 on plants. These are herbivorous animals, such 

 as cattle, horses, sheep. But even the flesh 

 which carnivorous animals eat— as dogs, cats — 

 is directly or indirectly derived from herbivo- 

 rous animals ; for "all flesh is grass." 



175. The round of life begins and ends with 

 the soil. The soil contributes to feeding the 

 plant, the plant feeds the animal, and the ani- 

 mal passes at last into the soil. In this round, 

 there is no creation of elements, and no loss ; 

 but there are endless combinations, and these 

 combinations break up and pass away. To 

 raise the plant, therefore, is the primary effort 

 in agriculture. 



5. The Plant has Intrinsic Value to Man 



5a. As articles of food or beverage 



176. Plants or plant -products may be staples 

 or necessaries, as wheat, rice, potatoes, beans ; 

 semi- staples, or articles of very general and 

 common use, as apples, oranges, buckwheat ; 



