=Remember.= 1. Clothing should be just heavy enough to keep the body warm all the time. 2. Never take off your coat or sit in a draft when you are too warm. 3. Since wearing damp clothing causes a great deal of sickness, change your clothes as soon as they become wet or damp. 4. Do not forget to take your umbrella when it is raining and to wear your rubbers when the ground is wet. 5. In cold weather wear your overcoat when you are outdoors, but take it off when you come into the house. CHAPTER IV THE USES OF FOOD We kill a great many of the cells in our bodies by starving them; either we do not give them enough food or we do not supply the right kind of food. [Sidenote: Why the body needs new cells] Not only must we feed the cells in our bodies, but we must be constantly making new ones, for in all our work or play, awake or asleep, we are constantly using up certain cells. These cells are used to make the body go, just as the engine uses coal to form the steam that gives it power to run. Boys and girls grow fast and, of course, if they expect to become well men and women, they must make a great many new cells all the time, in addition to those used in doing the work of the body. If we are to make new cells we must have the right kind of food with which to make them. [Sidenote: How the body keeps itself warm] We want to do something besides make new cells; we want to keep warm and well the cells we already have. No amount of clothing would keep you warm if you were not making heat inside your body all the time, any more than you could make a telephone post warm by putting your coat on it. Therefore it is necessary to have food that makes heat in the body, in addition to food that builds cells. We eat a great many kinds of foods, and all that we eat is used either for building new cells or for producing heat in the body. Thus we can divide all our foods into two classes--building material and heat-producing material. The type of building material is lean meat, and the type of heat-producing material is fat meat and starches, such as potatoes and bread. Milk contains much building material as well as heat-producing material. That is why a baby grows and keeps warm while he takes nothing but milk. [Sidenote: The building foods] Lean meat is the best of all building foods. Eggs are largely a form of lean meat, and hence constitute a good article of food for building purposes. Certain vegetables contain a large per cent of building material; this is especially true of dried beans and peas. Wheat flour and corn meal (particularly when made of whole wheat and unbolted meal) contain much building material.