=The Chewing of Food keeps away Sickness.=--Bread, meat, and potatoes should be cut into pieces no larger than half the size of your thumb and each piece put separately into your mouth with a fork. It should then be chewed from twenty to thirty times before another piece is put into the mouth. Food treated in this way will not cause headache or a sickness in the stomach called _indigestion_ or _dyspepsia_. It is said that there are so many persons with this kind of sickness that more than $5,000,000 are spent every year for medicine to help them. Too little chewing of the food while you are young may not cause many aches or pains, but if you form the habit of rapid eating it is hard to learn to eat slowly. No one who chews his food poorly can avoid sickness long or grow well and strong. [Illustration: FIG. 26.--Photograph of a chestnut chewed a half minute by a boy with good teeth.] =The Work of the Stomach.=--When the food is swallowed, it passes through the gullet into the stomach. This is a sac holding more than a quart (Fig. 27). It is made of an outer wall of muscle and an inner skinlike coat full of tiny tubes called _gastric glands_. Millions of these give out drop by drop a watery fluid named _gastric juice_. This juice begins to flow as soon as we smell or taste food and continues to drop out as long as there is any food in the stomach. The use of the gastric juice is to help change part of the food into a more watery fluid. To do this it must be well mixed with the food. This mixing is done by the muscles in the outer wall of the stomach (Fig. 29). They squeeze together and then loosen up in such a way as to move the food about and turn it over until every particle is wet again and again with the gastric juice. =How long Food stays in the Stomach.=--A ring of muscle around the end of the stomach keeps the food from escaping until it has become a thin grayish liquid. The stomach can finish its work on some kinds of food in one or two hours. With other foods it must work four or five hours. The stomach can finish its work on soft boiled eggs, milk, roasted potatoes, and broiled lamb within two hours. With pork, veal, cabbage, and fried potatoes it must work four or five hours. When a person is sick the stomach is weak, and he should have only the food which causes the stomach the least work. =The Work of the Intestines.=--The last part of the work in getting the food ready for the blood is done in the long folded tube known as the intestine (Fig. 27). Here juices coming from the pancreas and liver mix with the food and change into a liquid those parts not acted on in the stomach. The intestine does quite as much work as the stomach. Sometimes when the stomach is sick, too much work is put off on the intestines and then they become sick and give much pain.