WHY WE NEED FOOD.--We have learned that our bodies are constantly giving off waste matter--the products of the fire, or oxidation, as the chemist terms the change going on within us (Note, p. 107). A man without food will starve to death in a few days, _i. e._, the oxygen will have consumed all the available flesh of his body. [Footnote: The stories current in the newspapers of persons who live for years without food, are, of course, untrue. The case of the Welsh Fasting Girl, which excited general interest throughout Great Britain, and was extensively copied in our own press, is in point. She had succeeded in deceiving not only the public, but, as some claim, her own parents. At last a strict watch was set by day and night, precluding the possibility of her receiving any food except at the hands of the committee, from whom she steadily refused it. In a few days she died from actual starvation. The youth of the girl, the apparent honesty of the parents, and the tragical sequel, make it one of the most remarkable cases of the kind on record.] To replace the daily outgo, we need about two and a quarter pounds of food, and three pints of drink. [Footnote: Every cell in the tissues is full of matter ready to set free at call its stored-up energy--derived from the meat, bread, and vegetables we have eaten. This energy will pass off quietly when the organs are in comparative rest, but violently when the muscles contract with force. When we send an order through a nerve to any part of the body, a series of tiny explosions run the entire length of the nerve, just as fire runs through a train of gunpowder. The muscle receives the stimulus, and, contracting, liberates its energy. The cells of nerve or muscle, whose contents have thus exploded, as it were, are useless, and must be carried off by the blood, just as ashes must be swept from the hearth, and new fuel be supplied to keep up a fire.] Including the eight hundred pounds of oxygen taken from the air, a man uses in a year about a ton and a half of material. [Footnote: The following is the daily ration of a United States soldier. It is said to be the most generous in the world: Bread or flour . . . . . . . . . 22 ounces. Fresh or salt beef (or pork or bacon, 12 oz.) . 20 " Potatoes (three times per week) . . . . . 16 " Rice . . . . . . . . . . . 1.6 " Coffee (or tea, 0.24 oz.) . . . . . . 1.6 " Sugar . . . . . . . . . . . 2.4 " Beans . . . . . . . . . . . 0.64 gill. Vinegar . . . . . . . . . . 0.32 " Salt . . . . . . . . . . . . 0.16 "]