"I should have told you that a knowledge of the nature of the soil is one of the things that is very important to the agriculturist. Many men have made failures because they planted things which the earth was not adapted to grow."
"It has always been a wonder to me why things really do grow up out of the dirt," said Harry.
"That is not difficult to understand, if you will consider that the ground contains food, and that a plant can grow only where it can get the right kind. Then, there may be plenty of food but not the kind it can digest."
"Well, that is news to me. Do plants digest food?"
"Yes, just the same as what we call living animals. The tree is somewhat different from animals, in the particular that it digests its food first and then consumes it afterwards. In this particular certain larvæ act the same as trees, that is digest it before they consume it."
"What do you mean by larva?"
"The early form of certain living organisms, before they are fully developed. Thus, the tadpole is the larva of the frog. A great many insects are bred from what are called grubs, or caterpillars. All these are called larva."
"What kind of food is found in the earth?"
"Many, many kinds. Carbon, nitrogen, the various salts, such as lime, magnesia, strontia, and the like, and when the little feelers shoot out from the roots, they are in search of something to eat."