In still another way the sun is one of our best friends; for his rays have the wonderful power, not only of causing plants that supply us with food--the Green Plants, as we call them--to grow and flourish, but at the same time of withering and killing certain plants that do us harm. These plants--the Colorless Plants, we may call them--are the _molds_, the _fungi_, and the _bacteria_, or _germs_. You know how a pair of boots put away in a dark, damp closet, or left down in the cellar, will become covered all over with a coating of gray mold. Mold grows rapidly in the dark. Just so, these other Colorless Plants, which include most of our disease germs, grow and flourish in the dark, and are killed by sunlight. That is why no house, or room, is fit to live in, into which the sunlight does not pour freely sometime during the day. The more sunlight you can bring into your bedrooms and your playrooms and your schoolrooms, except during the heat of the day in the summer time, the better they will be. The Italians have a very shrewd and true old proverb about houses and light: "Where the sunlight never comes, the doctor often does." So you see that Nature is guiding you in the right direction when she makes you love and delight in the bright, warm, golden sunlight; for it is one of the very best friends that you have--indeed, you couldn't possibly live without it. In one sense, in fact, though this may be a little harder for you to understand, you are sunlight yourselves; for the power in your muscles and nerves that makes you able to jump and dance and sing and laugh and breathe is the sunlight which you have eaten in bread and apples and potatoes, and which the plants had drunk in through their leaves in the long, sunny days of spring and summer. So throw up your blinds and open your windows wide to the sunlight every morning; and let the sunlight pour in all day long, except only while you are reading or studying--when the dazzling light may hurt your eyes--and for six or seven of the hottest hours of the day in summer time. Perhaps your mothers will object that the sunlight will fade the carpets, or spoil the furniture; but it will put far more color into your faces than it will take out of the carpets. If you are given the choice of a bedroom, choose a room that faces south or southeast or southwest, never toward the north. II. A GOOD START When you are really awake and have had a good look to see what kind of morning it is, you will feel like yawning and stretching, and rubbing your eyes four or five times, before you jump out of bed; and it is a good plan to take plenty of time to do this, unless you are already late for breakfast or school. It starts your heart to beating and your lungs to breathing faster; and it limbers your muscles, so that you are ready for the harder work they must do as soon as you jump out of bed and begin to walk about and bathe and dress and run and play.