But the more general result is a gradual undermining of all parts of the human frame; this imperceptibly shortening life, by so weakening the constitution, that it is ready to yield, at every point, to any uncommon risk or exposure. Thousands and thousands are parsing out of the world, from diseases occasioned by exposures which a healthy constitution could meet without any danger. It is owing to these considerations, that it becomes the duty of every woman, who has the responsibility of providing food for a family, to avoid a variety of tempting dishes. It is a much safer rule, to have only one kind of healthy food, for each meal, than the too abundant variety which is often met at the tables of almost all classes in this country. When there is to be any variety of dishes, they ought not to be successive, but so arranged as to give the opportunity of selection. How often is it the case, that persons, by the appearance of a favorite article, are tempted to eat merely to gratify the palate, when the stomach is already adequately supplied. All such intemperance wears on the constitution, and shortens life. It not infrequently happens that excess in eating produces a morbid appetite, which must constantly be denied. But the organization of the digestive organs demands, not only that food should be taken in proper quantities, but that it be taken at proper times. [Illustration: Fig. 56.] Fig. 56 shows one important feature of the digestive organs relating to this point. The part marked LM shows the muscles of the inner coat of the stomach, which run in one direction, and CM shows the muscles of the outer coat, running in another direction. As soon as the food enters the stomach, the muscles are excited by the nerves, and the _peristaltic motion_ commences. This is a powerful and constant exercise of the muscles of the stomach, which continues until the process of digestion is complete. During this time the blood is withdrawn from other parts of the system, to supply the demands of the stomach, which is laboring hard with all its muscles. When this motion ceases, and the digested food has gradually passed out, nature requires that the stomach should have a period of repose. And if another meal be eaten immediately after one is digested, the stomach is set to work again before it has had time to rest, and before a sufficient supply of gastric juice is provided.