It should be remembered, however, that for the strengthening of the stomach one must really depend most of all upon a proper diet and the care of the stomach generally, rather than upon any system of exercises intended to invigorate this organ. To build up a strong stomach a daily plan of life must be followed which requires of the entire body a normal amount of activity, thus demanding and using a fairly liberal supply of nourishment. An active life is always favorable to good digestion, and especially so if it is an out-of-door life for at least a large part of each day, for then an appetite is created demanding of the stomach that healthy activity essential to strength building; in other words, an active and normal life generally is essential to the maintenance of a strong and healthy stomach. The body must be regarded not as an aggregation of parts, but as one complete unit, and anything that affects all parts affects each separate part. It is quite true that when the stomach is weakened from any cause, it is not wise to overtax it by the ingestion of foods that are difficult to digest. But at the same time a policy of using predigested foods, or others that are suited only to a weak stomach, is not likely to develop a vigorous digestion. It is essential that one should use a proper supply of natural and wholesome foods properly prepared. If this is done and the general rules of rational dietetics are observed, there is no reason why any one should not enjoy the possession of a strong stomach and a vigorous digestion. I cannot, however, place too much emphasis upon the value of outdoor life and general activity and the constitutional benefits that go with them for improving the stomach as well as all other parts of the body. CHAPTER XI: Preserving the Teeth Health to a large extent depends upon the teeth. Food can not be properly masticated without sound molars. The modern tendency of teeth to decay early in life clearly proves that something is wrong with our dietetic or chewing habits. Like any other part of the body, the teeth must be exercised in order to be properly preserved. Our foods are so frequently macerated to a fine consistency and they are so often cooked to a mush before they are eaten, that the teeth have little to do. They decay and become soft or brittle because of lack of use.