[Footnote 36: The “difference” is in the digestibility, and in guarding against excess: Overeating is, of itself, a positive guarantee of indigestion.[A] The advantages of the hard bread and “dry diet” are manifold: (1) thorough mastication——calling the muscles of the mouth into action, and while this tends to make the cheeks plump and full, the exercise affects the various glands, and aids in the secretion of the salivary fluids essential for the digestion of starch;[B] (2) it causes one to eat slowly, so that each mouthful entering the stomach; is not only thoroughly insalivated and thus prepared for stomach-digestion, but can be thoroughly manipulated in the stomach and impregnated completely with the gastric juice: this must be deemed a very important feature, when we reflect that in very depraved states the digestive fluids are not as abundant nor as readily secreted as in health. (3) Chewing strengthens the gums and the teeth,——tends to preserve them and fit them for their legitimate work: decaying teeth are a source, as well as a symptom, of disease.] [Footnote A: In accordance with a universal law of nature,——“the conservation of energy,”——“gastric juice,” upon which digestion depends, “is secreted from the blood by the glands of the stomach, in proportion to the needs of the organism for food, and not in proportion to the amount of food swallowed.” There is, therefore, a normal dyspepsia for whatever of excess is taken. Moreover, in such cases, none of the food is well digested.] [Footnote B: _Ptyalin_, a vegetable matter contained in healthy saliva, has very peculiar properties: “if mixed with starch and kept at a moderate warm temperature, it turns that starch into grape-sugar. The importance of this operation becomes apparent when one reflects that starch is insoluble, and therefore, as such, useless as nutriment, while the sugar formed from it is highly soluble, and readily oxidizable.”——HUXLEY.]