The great importance of this can be easily realized if we observe the face of any one who has been constipated for several days. After a thorough clearing out, the face becomes fresher and the eyes brighter. The complexion that was previously a dirty gray becomes white and rosy again, particularly in the case of young women. Should not this prove an object lesson as to the vital importance of a thorough evacuation daily as a safeguard against premature old age? Every physician who practices in a place where the mineral waters have purging effects has occasion to observe that persons coming to these spas, looking worn out and gray in the face, with pendant cheeks, and showing all the signs of auto-intoxication from the retention of poisonous products, always look much fresher, and, indeed, many years younger, after the cure. We could observe the same effects in our own case after each purge, although we do not suffer from habitual constipation. There is no doubt that freedom from occupation, and particularly life in the open air, in the woods and meadows, have a very great influence in effecting such cures; but we may note the same effects after courses of purging without the aid of such conditions as the above. The care, not only of the bowels, but of the skin, must be impressed on every one from earliest childhood, especially the necessity of a bath daily. Unfortunately, this is too much neglected on the Continent, and becomes prevalent only as Anglo-Saxon customs are diffused abroad. By a bath with soap the pores of the skin are better opened, as the dirt that clogs them is removed, and thus the poisonous products can be given off through the skin more easily, and the skin thereby justifies its name as chief assistant to the kidneys. It is, in fact, our second kidney. When the skin comes into greater activity through the action of the sudorific glands, a part of the solids in the urine and many harmful matters, which otherwise would make their way through the kidneys, are eliminated through the skin instead, in which manner the powers of the kidneys are economized. It is, therefore, only natural that we should do everything to promote these important functions, especially since we may regard the skin not only as a second kidney, but to a certain extent also as a second lung; for it possesses respiratory functions in addition, receiving oxygen and giving off carbonic acid to a certain degree. To assist these functions in every possible way, we must allow the air to reach the skin freely, for which purpose clothing and underwear should be porous, in order not to impede the process of respiration and elimination. This end will also be attained by exercise in the open air and sunshine; in fact, by remaining out-of-doors as long as possible. All these important features will be dealt with fully in separate chapters.