Inasmuch as the several nutritive elements found in a single article of food are better proportioned by Nature, than man can usually proportion them, the relation of one substance to another will be better divided if the entire meal be made to consist of only one kind of food, and both digestion and assimilation will therefore be more perfect. Under these conditions the blood will be laden with very little waste matter, which is the thing that reduces our powers of endurance. Therefore, when it is possible to secure the carbohydrate, the proteid, and the fatty substances from a single article of food which will give to the body greater strength and endurance than when we secure these substances from several sources, we should confine our menus to single articles of well-proportioned food. This thought, carried to its logical end, leads one more and more, as experience progresses, toward the mono-diet system. PURPOSE OF MINERAL SALTS Mineral salts serve two distinct purposes in the body: 1 They assist in building up the cartilage and the body-structure 2 They assist in the digestion, and in the dissolution of other foods, especially of the carbohydrate group, and more especially of the grain family Grains are very difficult to subdivide into their constituent elements; that is, to reduce to a solution so fine that assimilation will be perfect. A liberal use of the foods containing mineral salts aids very materially in this process of solution. DIFFERENCE BETWEEN DIGESTIBILITY AND ASSIMILABILITY The true interpretation of the word "digestion" is the preparation of food by the action of: 1 The saliva 2 The gastric juice 3 The bile, and 4 The pancreatic juice When food is properly prepared by mastication by the time it reaches the pancreas, it should be thoroughly split up or subdivided, in which state it is ready for assimilation. The true interpretation of the word "assimilation" is the absorption of all food substances through the walls of the intestinal tract, and the final passing of them into the circulation. It is nothing unusual, however, for a person to become afflicted with predigestion, and, at the same time, with poor or faulty assimilation; in other words, digestion being too rapid, and assimilation being too slow. This condition frequently occurs in cases of superacidity. On account of the excess of acid, the food digests or passes from the stomach prematurely; that is, before it has been dissolved by the action of the hydrochloric acid. The food, thus super-charged with acid, passes from the stomach into the lower intestines, and sets up a condition of irritation. This irritation or swelling of the mucous surface (lining) of the intestines, closes the small canals, or winking valves, as they are sometimes called, thus seriously interfering with the passing of the dissolved food matter into the circulation. * * * * *