State what you can of sugar--its origin and various qualities. 60, 61 21. Of starch--its varieties and qualities. 61 22. Of the abundance of starch, and its importance as a food principle. 61 23. What is stated in relation to stimulating substances? 62 24. Of the necessity for regulation in diet? 62, 63 * * * * * {64} CHAPTER V. FOOD AND DRINK. _Necessity for Food--Waste and Repair--Hunger and Thirst--Amount of Food--Renovation of the Body--Mixed Diet--Milk--Eggs--Meat--Cooking--Vegetable Food--Bread--The Potato--Fruits--Purity of Water--Action of Water upon Lead--Coffee, Tea, and Chocolate--Effects of Alcohol._ [Sidenote: 1. What follow activity? Examples? Necessity for food?] 1. NECESSITY FOR FOOD.--Activity is everywhere followed by waste. The engine uses up coal and water to produce motion, the stream wears away its bank, the growing corn-blade draws tribute from the soil. When the human body acts, and it is always in action during life, some of its particles are worn out and thrown off. This waste must constantly be repaired, or the body suffers. In this fact is seen the necessity for food. The particles, thus worn out, being henceforth useless, are removed from the body. Our _food_ and _drink_ are rapidly transformed into a new supply of living, useful material, to be in turn used up and replaced by a fresher supply. [Sidenote: 2. Give the theory in relation to waste and repair.] 2. WASTE AND REPAIR.--In this way the healthful body, though always wasting, is always building up, and does not greatly change in size, form, or weight. At two periods of life the processes of waste and repair are not exactly balanced. In early life the process of building up is more active, and in consequence the form is plump, and the stature increases. Repair now exceeds waste. On the other hand, when old age comes on, the wasting process is more active, the flesh and weight diminish, the skin falls in wrinkles, and the senses become dull. Only during the prime of life--from about twenty to sixty years of age--is the balance exact between loss and gain. {65} [Sidenote: 3. System deprived of food? Warning? What is the pain? How proved?] 3. HUNGER AND THIRST.--When the system is deprived of its supply of solid food during a longer time than usual, nature gives warning by the sensation of hunger, to repair the losses that have taken place. This sensation or pain appears to be located in the stomach, but it is really a distress of the system at large. Let a sufficient quantity of nourishment be introduced into the system in any other way than by the mouth, and it will appease hunger just as certainly as when taken in the usual manner. [Sidenote: 4. Feeling of thirst? Seat of the pain? How proved? Time a person can exist without food?]