Inasmuch as the body is nearly two-thirds water, it follows that the diet should be composed of about 66 per cent moisture. The old theory of dietitians that no water should be taken with meals was based upon the hypothesis that the water diluted the gastric juice, and that this diluted form of the gastric juice weakened its digestive power. Actual practise has proved this thesis to be untrue. Water is the great universal solvent, and the hydrochloric acid of the stomach is only a helper, as it were, in the dissolution or the preparation of food for digestion. Water is also a valuable agent in the elimination of body-poisons. [Sidenote: Value of water to blood] The liberal use of water keeps the blood supplied with the necessary moisture, and that excess which is eliminated through the kidneys carries away poisons that would reside in the body very much to the detriment of health. There is little danger, therefore, in drinking too much pure water, but much care should be exercised that it be pure, or at least free from lime and mineral deposits. The best water is pure water, free from all mineral substances. [Sidenote: When water drinking is unnecessary] [Sidenote: Disorders caused by insufficient moisture] If a meal consists of watery food, such as fresh vegetables, salads, etc., then the drinking of water becomes unnecessary; but where the meal is composed chiefly of solids, then an amount of water should be taken sufficient to make up 66 per cent of the total. If more water is taken than is necessary for this purpose, the excess will pass off and the stomach will only retain the necessary amount; but if the quantity of moisture is insufficient, the stomach calls to its aid an excess of hydrochloric acid, the strength of which has a tendency to crystallize the starch atom (especially cereal starch), thereby causing the blood-crystal, which is one of the primary causes of rheumatism, gout, lumbago, arterial sclerosis (hardening of the arteries), and all disorders caused by congestion throughout the capillary and the arterial systems. The most common disorder among civilized people is hydrochloric acid fermentation. Copious water drinking at meals is the logical remedy for this disorder. The proper amount of pure non-mineral water taken with food will do much to remove the causes of superacidity and the long train of ills that follow this disorder. (See "Chart," Lesson I, page 9.) In this work I shall constantly refer to these various uses of water, especially as a solvent (an aid to digestion), and as a remedial and curative agent. [Sidenote: Man's source of water]