247
fact more naturally by stepping from an atmosphere of 75° F. into a tub of water at the same temperature. The latter always feels cool. For these reasons a thermometer should usually be consulted when using water baths or treatments involving immersion to give with safety the desired reaction to the body. Mechanical friction can be employed to enhance the effect of water treatments. The application of cold, combined with friction, can act cooperatively to produce a much greater influence than either alone. The same is true of water douches and sprays. The percussive effect of a water stream adds greatly to the reaction produced, partly because of the perfect fluidity of water as a solvent. As a cleansing agent, water is used in shampoos, the enema, and the douche. The benefits from drinking pure soft water are partially due to dissolving and washing out poisons from the system, and the beneficial cleansing effect on kidneys and bowels. Some waste products in our bodies require a great deal of water to dissolve them. Furthermore, constant hydration of the tissues must always be maintained. For these and countless other reasons, water is a great blessing to mankind. How The Skin Works As indicated in Chapter 9, the largest organ of the body is the skin. Some writers have called it “keyboard of the hydrotherapist.” Through the numerous blood vessels and nerves of our skin, and their reflex connections with the internal organs, practically every organ of the body can be influenced by applications of heat or cold to the skin surface. Small muscle bundles are found in the dermis, connected with the hair follicles. Contraction of these arrectores pilorum muscles cause the hair to stand erect, producing a peculiar roughness of the skin known as “goose flesh.” Applications of cold or sensations of chilliness can bring this condition. With cold, the skin also becomes blanched, as blood squeezes out of the vessels by this muscular contraction. An enormous network of lymphatic vessels, veins, and capillaries is present. These tiny tubes that constantly convey fluid back to the heart contain thousands of valves and nerve fibers. This gives them the ability to shift blood flow from one area to another. Several times a minute, changes occur in the diameter of our blood vessels. As they contract and become smaller, blood is forced onward. During the relaxing or dilating phase, they fill with blood. This “pumping” action is another powerful factor in the circulation of these vital fluids. It is sometimes called the “peripheral heart.” Circulation slows when the nerve control of these vessels is interfered with, and the extremity becomes dusky in color and cold. Paralysis succeeding a stroke, infectious diseases, and even emotional