Every day we are getting rid of the superficial layers of the skin, which process can become so intense in some people that the skin looks as though it were covered with flour dust; and in some persons with dry skin such apparel as stockings sometimes gets full of this. These minute scales, which get necrotised in the upper parts of the skin, are apt to clog the pores, which can also become closed by particles of dust, or by products of the sebaceous glands and by perspiratory residues. As the free entrance of air to the pores is an essential condition for skin respiration, and as the elimination of harmful products is only possible when the pores remain open, we must get rid of the foreign matters which clog them, for which purpose we take a bath. But water alone, even if it be hot, is not able to effect a thorough cleansing of the skin on account of the oily substance which is secreted by the sebaceous glands; so, to obtain the fullest cleansing effects, we add the use of soap and a brush, as already mentioned before. We must rub the soap well in, and then rub it off energetically, if we desire to benefit by a fully hygienic bath.
As we are daily getting rid of the above-mentioned skin scales, so it behooves us to take a daily bath. It is not necessary to stay in the bath more than ten to twelve minutes, or at the most fifteen. For the reasons above mentioned the effect of bathing is a rational hygiene of the skin.
By the action of the water, soap, and brush friction the skin receives more blood, which is, at the same time, a great advantage to the internal organs, as the blood drawn away from them facilitates the circulation through them should they be congested. When more blood reaches the skin the muscles that contract the pores are also better nourished, and they then react better to certain agencies—cold, for instance. They quickly contract the pores, so that the blood will be kept back in the interior of the body and a cooling off of the periphery of the body, with its dangerous consequences from catching cold, may thus be avoided.
A daily bath can also be advantageous for those who perspire too freely. After a bath, and this is one of its greatest advantages, the insensible perspiration is much increased, and more water leaves the body through the pores than before, and when a bath has been too hot, a very free perspiration may ensue. But usually with people with a too free perspiration, this tendency would be diminished, as it can often be noted that those who daily take a lukewarm bath perspire less than others on warm summer days.
Besides exciting the functions of the skin baths are also an excellent means for diminishing a possible overwork of the kidneys, and thus keeping them in good condition. It is possible to eliminate, through bathing, such products by the skin which otherwise would have to be eliminated through the kidneys.
It has recently been shown by experiments conducted by Strasser and Blumenkranz[237] that baths taken for a long time and at a temperature of 34-35°C., are able to create an increased elimination, not only of a considerable quantity of water, but of common salt also, and of the products of decomposition of nitrogenous matter.
These authorities come to the conclusion that through bathing there can be brought about a true increase not only of the water-secreting activity of the kidneys, but also of their ability to eliminate nitrogenous end-products and salt. They found an increase of diuresis to double the usual amount and an increased elimination of from 50 to 100 per cent. of nitrogen, and from 100 to 200 per cent. of salt. According to Liebermeister, Loewy, Rubner, and others, the processes of oxidation can be increased by cold baths from 50 or 100 to 200 per cent., and by hot baths, according to Winternitz and Rubner, 50 to 100 per cent. Rubner also asserts that the processes of oxidation can be wonderfully increased by cold douches.
There can thus be no doubt that baths are able to influence the conditions of the kidneys in a very favorable way, and that their vitality may be augmented by the daily use of the bath.
The drawback to the bath is that so many people easily catch cold afterward; to prevent which, such persons should not wet the head, and especially the back part of it, as otherwise catching cold is easily effected; and it is also of importance that the bath-room should not be left while the skin is hot. The best way is to allow cold water gradually to enter the bath, getting out directly there is the least sensation of cold. The rule should be not to leave the bath when the skin is hot and red and the pores wide open, without letting cold water contract them by taking a short douche, and on getting out of the bath the skin should be quickly dried by energetic friction with a rough towel until the skin becomes quite scarlet. Not sufficiently drying the skin will cool it rapidly, and even intensely, owing to the evaporation of the water from the periphery, and surely cause a severe cold.
To prevent the habit of catching cold the best way is to accustom the skin to the action of cold water. Rubbing the skin with a cold wet towel until the skin glows, especially the chest and extremities, is a good way to effect this, beginning in warm summer weather and continuing through the winter, but not vice versa. Decidedly the best preventative to catching cold is to get the skin accustomed to fresh air and cold water.
To prevent catching cold after a bath a reaction of the skin is necessary, and this is best attained by a rough towel, as before mentioned, and by rubbing the body with a hard brush. Massage is an excellent addition to bathing, as by this means the circulation through the skin and muscles is much increased, thereby increasing the oxidation of the body. By kneading the muscles waste products are brought into the lymphatics (see, also, chapters on exercise).
It is only logical that we must pay special attention to cleanliness in those parts that have the greatest number of sudorific glands, such as for example the axillæ and the toes of the feet. Circumstances often, as when on a journey, do not allow of the luxury of a complete bath, and in such cases we must be content to wash the body with water and soap, and to rub down with a rough towel and brush, paying particular attention to the axillæ and feet. These may also be bathed in alcohol and water, ½ to ⅓ of the latter, and also with vinegar and water; the feet can best be cleansed in a foot-bath.
From ancient times, especially in the East, such foot-baths have been largely used, probably for the reason that sandals were worn, which allowed dust and dirt to accumulate on the feet; people whose feet perspire freely should always use a foot-bath daily; and, because the feet are a part of the body which are the worst aërated from being covered with impermeable leather, while they are, at the same time, the best provided with sudorific glands, a daily foot-bath is advised for all.
When the feet perspire freely, hot water must be used; but after using such we must immediately use cold water so that the opened pores will close again. Pouring cold water into the bath or over the feet will effect this, but it must be done quickly.
Foot-baths are excellent things for those who suffer from cold feet, and what at first sight seems paradoxical, a cold foot-bath in particular, which acts by enlivening the circulation in the feet; the bathing should, however, only last about a couple of minutes. Cold baths for the feet also act very beneficially in cases of headache, and especially in insomnia. They act upon the distribution of blood in the brain; the blood-vessels are thereby first distended and afterward they contract, which, lasting for a certain time, induces sleep; for, as mentioned in the chapter on sleep, the brain must be free from blood if sleep is to result. In hot summer weather it is quite delightful to sit on the banks of a river and allow our feet to dangle in the water, and we always feel refreshed after it; walking with bare feet is also very pleasant and healthy in summer time.
The action of a foot-bath is much increased by the addition of salt or mustard, and with the latter is an excellent preventative against a hyperæmic condition of the brain, such as apoplexy, as thereby we favor a decreased congestion of this noble organ.
Cold foot-baths should not be used by very old people, as they distend the brain-vessels which, as a rule, are altered in such people and may more easily rupture; if taken, a wet, cold towel should be wound round the head.
Cold baths generally are often beneficial in the case of certain nervous troubles, such as neurasthenia and hysteria; only they must never be too cold nor too prolonged, as otherwise the effects may be very depressing. A short cold friction of the body every morning on rising is of great advantage in the preservation of health. In kidney trouble we must, however, be careful, as often an increase of albuminuria has been observed after them. Sea baths are especially refreshing, owing to the sodium content of the salt water. Our own observations teach us that a bath had best be taken by first using water of the highest temperature that can be borne (about 42 degrees C.). Those who can stand it might continue to add hot water until the skin is quite red. Abundant perspiration will then appear on the head, face, and neck. After having perspired freely, we should then allow cold water to enter until the bath has become cool. It usually takes some time to cool the water off thus gradually, but after such a bath there is a feeling of great exhilaration, especially after warm sea baths taken in this manner. We consider that hot baths of long duration—say 30 to 45 minutes—are especially useful in cases of kidney disease, or as a preventive of such. We could take them twice a week as a means of eliminating the toxic products of metabolism, but it is an essential condition that the heart and blood-vessels be in good condition. The Japanese are in the habit of taking such hot baths at an enormously high temperature, and they feel the better for it.
Bathing generally is favorable not only to the kidneys, but to all the organs, as the processes of oxidation are thereby promoted, and our prospects for long youth and long life are bettered.