The uses of water in the body may be roughly grouped into three
divisions, as follows:
1 Water in small quantities enters into the actual chemical
composition of the body.
As we will notice in the discussion of carbohydrates, water
combines chemically with cane-sugar when it is digested and
transformed into glucose. (See Lesson IV, "Cane-sugar," page 112.)
2 Water forms a portion of the tissues and acts as a solvent
in the body-fluids.
[Sidenote: What blood carries in solution]
In this function the water is not changed chemically, but is
only mixed with other substances; thus the blood is in reality
water with glucose, peptone, etc., in solution, and carrying along
with them red blood-corpuscles and fatty globules.
3 Water is a most important factor in the digestion, and the
assimilation of food, and the elimination of waste.
[Sidenote: Drinking with meals]
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]
Theories have been promulgated by hygienic teachers in the past few
years that man should get his supply of water wholly from the juices of
fruits, and not drink ground-waters, which are contaminated with mineral
substances. While it may be true that water in certain localities, such
as in the alkali deserts, is unfit for drinking, yet the writer believes
that the promulgators of the theory that man is not a drinking animal
never did a hard day's work in a harvest field. In the dry winds of the
western plains water evaporates from the surface of the body at the
rate of twelve or fifteen pounds a day. The theory of deriving one's
water supply wholly from fruits would not stand the test of such facts.