This section is from the "A Practical Treatise On Materia Medica And Therapeutics" book, by Roberts Bartholow. Also available from Amazon: A Practical Treatise On Materia Medica And Therapeutics
Aqua, water; eau, Fr.; Wasser, Ger.; Aqua destillata, distilled water—water freed from its organic and inorganic impurities by distillation. This is alone official.
Well or spring water.
Water as a remedial agent, when employed in internal maladies, and as a means of applying heat and cold externally, are the departments of the subject coming within the scope of this article.
Internal.—It need hardly be stated that water is an essential constituent of the tissues.
A certain quantity of water or fluid aliment is necessary to the digestive process. An excessive quantity impairs digestion, by so far diluting the gastric juice as to render it incapable of dissolving the foods. Pepsin—the digestive ferment—is also weakened by too great fluidity of the stomach contents. The free use of cold drinks—ices and iced water—seriously disorders digestion by suspending the action of the pepsin, by diminishing the blood-supply needed by the stomach in its condition of functional activity, and no doubt also by depressing the nerves of the organs of digestion. To this state, induced by the free use of very cold drinks during meals, or during the time of digestion, has been applied the term "ice-water dyspepsia" a very common malady in the United States.
A glass of cold water in the morning before breakfast will in many persons cause a satisfactory evacuation of the bowels. The activity of the water is increased by the addition to it of a teaspoonful of common salt.
Although water is essential to the constitution of the fluids and solids of the body, there is no doubt that large and frequent draughts of water may prove injurious by too great increase in the fluidity of the blood, and a consequent damage to the red corpuscles.
The free use of water promotes nutritive changes, and causes in some subjects a decided increase in the formation and deposition of fat. The presence of water is essential, of course, to the metamorphosis of tissue, whether physiological or pathological. The efficacy of mineral waters is in part due to the quantity of water taken, besides the mineral constituents. Water may be taken with the view to cause increased excretion of certain substances. As a large part of that taken passes out by the kidneys, the functional activity of these organs is promoted by free drinking. With the water also passes out an increased amount of urea, chloride of sodium, and phosphoric acid, the product of the more rapid tissue-changes which ensue. The increased elimination of chloride of sodium does not continue, however.
Water is also excreted by the skin, and free water-drinking promotes the cutaneous transpiration, especially when its action is aided by external warmth. The vapor of water also passes out abundantly in the breath.
External.—The influence of temperature must necessarily be considered in connection with the effects of water when applied externally.