NATURE STUDY AND 
AGRICULTURE 
CHAPTER I 
PLANTS: IMPORTANCE, CULTIVATION, AND IMPROVEMENT 
Importance of Plants. — The earth is the source of all 
‘wealth. From the earth’s crust we get stone and clay for our 
building materials, coal for our fuel, and iron and other metals 
so necessary for our modern industries. But the plants 
produced by the earth are the most important source of all 
wealth, for without them all animals, including man, would 
starve. 
Plants take from the earth and the air the inorganic sub- 
stances on which they are nourished and make them into the 
organic substances on which animals feed. The vegetable 
kingdom thus serves as a connecting link through which the 
mineral kingdom indirectly supports the animal kingdom. 
Even if we live partly on meats, we must bear in mind that 
the animals from which these meats come are dependent upon 
a vegetable diet. 
Moreover, we are not only indebted to plants for our bread, 
our fruits, and our vegetables, but also for lumber to build 
our homes, fibers to make our clothing, and drugs to make us 
well when we are ill. 
