If there is more dyspnea than normally should occur in the individual patient after walking rapidly or climbing a hill or going upstairs, or if after a period of a little excitement one finds that he cannot breathe quite normally, or that something feels tight in his chest, the heart needs resting. If, after one has been driving a motor car or even sitting at rest in one which has been going at speed or has come unpleasantly near to hitting something or to being run into, it is noticed that the little period of cardiac disturbance and chest tension is greater than it should be, the heart needs resting. If the least excitement or exertion increases the cardiac speed abnormally, it means that for many minutes, if not actually hours during the twenty-four, the heart is contracting too rapidly, and this alone means muscle tire and muscle nutrition lost, even if there is no actual defect in the cardiac muscle or in its own blood supply. If we multiply these extra pulsations or contractions by the number of minutes a day that this extra amount of work is done, it will easily be demonstrable to the physician and the patient what an amount of good a rest, however partial, each twenty-four hours will do to this heart. Of course anything that tends to increase the activity of the disturbance of the heart should be corrected. Overeating, overdrinking (even water), and overuse or perhaps any use of alcohol, tobacco, tea and coffee should all be prevented. In fact, we come right to the discussion of the proper treatment and management of beginning high blood pressure, of the incipiency of arteriosclerosis, of the prevention of chronic interstitial nephritis, and the prevention of cardiovascular-renal disease. When an otherwise apparently well person begins to complain of weariness, or perhaps drowsiness in the daytime and sleeplessness at night, or his sleep is disturbed, or be has feelings of mental depression, or he says that he "senses" his heart, perhaps for the first time in his life, with or without edema of the feet and legs, or pains referred to the heart or heart region, we should presuppose that there is weakening of the heart muscle until, by perfect examination, we have excluded the heart as being the cause of such disturbance.