Climbing high mountains should be strictly forbidden persons suffering from disease of the heart and arteriosclerosis, for the greater exertion then required has often caused death in persons so afflicted. To prevent the bad circulatory effects of climbing it is necessary to breathe deeply and regularly, and this, indeed, should not be overlooked in all forms of exercises; even masseurs are unable to work properly unless they take deep regular breathing. In mild cases of heart trouble, and even in more serious cases if applied judiciously, Oertel’s treatment of each day slowly walking up a steeper and steeper hill will give good results, giving good training for the heart-muscle. But this treatment should only be carried out under the direction of a competent specialist. The great advantage of the various kinds of sport and of walking, climbing, and running exercise is that several other agencies can be combined with them that are very important in the treatment and prevention of the effects of old age. These are fresh air and sunshine. We think that the combination of the three agencies—exercise, fresh air, and sunshine—is the best and most necessary means for the preservation of youthfulness and for the prolongation of life. ------------------------------------------------------------------------ CHAPTER XXIX. A FEW REMARKS ON COLD FEET—THEIR CAUSE AND TREATMENT. IT is intentional that we present this chapter immediately after those on the improvement of the functions of the skin and on exercise, as these are the principal means by which, as a general rule, we are able to prevent cold feet. These are, for the most part, occasioned by an insufficient supply of arterial blood to the extremities. This can be caused either by a hindrance to the circulation—as for example in the case of irrational use of articles of clothing—or through the want of muscular contraction by exercise. In old people, especially, cold feet can be occasioned by the degenerative alterations of the blood-vessels, in consequence of which less arterial blood reaches the feet. If to this anatomical cause there are other factors added, then naturally the sensation of cold feet will much more easily result. We must bear in mind that the feet, like the nose also, are the most distant parts of the body from the center of the circulatory system—the heart, so that naturally in these parts, through the less effective warmth of the arterial blood in old people, and even in younger anæmic women, the sensation of cold will easily arise.