LESSON I
USES OF FOOD
The lesson may be introduced by asking the class to think in what way the body of a healthy baby, who is fed regularly, will have changed at the end of six months. It will be larger; it will have more flesh, more bone, more hair, etc. We want to get a name that will apply to any part of the body. No matter which part we examine through a microscope we find the same fine and beautiful texture, and to this we give a name similar to that given to fine, thin paper. We call it tissue—hair tissue, bone tissue, flesh tissue.
What has food done to the baby's tissues? It has enlarged its tissues; the child has grown larger. To the enlargement, or growth, of the tissues, we may apply the term, build, suggested by the building of a house. Then what may we say food does for the tissues of the body? We may say that food builds the tissues of the body.
Think of some persons who have taken food every day, and yet as long as you have known them they have not increased in size. What has food done for their tissues? The class must be told that the tissues of our bodies wear out through use, and that food has furnished the material to replace the worn-out parts. What do we say we are doing to clothes when we replace the worn parts? We are mending or repairing them. What does food do for our worn-out tissues? Food repairs the tissues of the body.
Do not think any more about the tissues of the body. Suppose you had not been able to get any food for several days. In what way would you be different from what you are now? You would not be as strong. Food gives strength or energy by being burned inside the body. There is a fire burning in our bodies all the time we are alive, the fuel being food. What do we require from the fire in our homes? We require heat. The fires in our bodies give us heat also. Any fire gives off both heat and energy. State another use of food to the body. Food produces heat and energy in the body.
But food does more for the body; it contains substances to keep our bodies in order. Suppose the clock gets out of order and does not keep good time, what does the watchmaker do to it? He regulates it. That is what certain kinds of food do for us. What then is another use of food? Food regulates the body.
Name the uses of food to the body.
1. It builds the tissues.
2. It repairs the tissues.