246. Baths and Bathing. In bathing we have two distinct objects in view,—to keep the skin clean and to impart vigor. These are closely related, for to remove from the body worn-out material, which tends to injure it, is a direct means of giving vigor to all the tissues. Thus a cold bath acts upon the nervous system, and calls out, in response to the temporary abstraction of heat, a freer play of the general vital powers. Bathing is so useful, both locally and constitutionally, that it should be practiced to such an extent as experience proves to be beneficial. For the general surface, the use of hot water once a week fulfills the demands of cleanliness, unless in special occupations. Whether we should bathe in hot or cold water depends upon circumstances. Most persons, especially the young and vigorous, soon become accustomed to cool, and even cold water baths, at all seasons of the year. The hot bath should be taken at night before going to bed, as in the morning there is usually more risk of taking cold. The body is readily chilled, if exposed to cold when the blood-vessels of the skin have been relaxed by heat. Hot baths, besides their use for the purposes of cleanliness, have a sedative influence upon the nervous system, tending to allay restlessness and weariness. They are excellent after severe physical or mental work, and give a feeling of restful comfort like that of sleep. Illustration: Fig. 105.—Epithelial Cells from the Sweat Glands. The cells are very distinct, with nuclei enclosing pigmentary granulations (Magnified 350 times) Cold baths are less cleansing than hot, but serve as an excellent tonic and stimulant to the bodily functions. The best and most convenient time for a cold bath is in the morning, immediately after rising. To the healthy and vigorous, it is, if taken at this time, with proper precautions, a most agreeable and healthful luxury. The sensation of chilliness first felt is caused by the contraction of the skin and its blood-vessels, so that the blood is forced back, as it were, into the deeper parts of the body. This stimulates the nervous system, the breathing becomes quicker and deeper, the heart beats more vigorously, and, as a consequence, the warm blood is sent back to the skin with increased force. This is known as the stage of reaction, which is best increased by friction with a rough towel. This should produce the pleasant feeling of a warm glow all over the body. A cold bath which is not followed by reaction is likely to do more harm than good. The lack of this reaction may be due to the water being too cold, the bath too prolonged, or to the bather being in a low condition of health. In brief, the ruddy glow which follows a cold bath is the main secret of its favorable influence.