The need of rest is as great as the need of the right sort of exercise. Late hours should be absolutely avoided and little brain work should be done in the evening, so that the brain and all its important arteries can sink into relaxation and sleep at once. The rest to the heart and circulation is of course never so prolonged, but nature has designed them to get their rest only in moments. The heart in an adult rests more than thirteen hours out of the twenty-four, under quiet normal conditions, the time of rest being the diastole, and the time of work being the systole or contraction. There are few healthy men who could not walk a thousand miles in six weeks, walking about eight hours a day and resting for the remainder of their time; but there are not many men who could walk a thousand miles in a thousand consecutive hours, as the late Captain Barclay did, because the frequent interruptions to their sleep would exhaust them completely. In the same way, if the heart is forced to beat more quickly, it becomes sooner exhausted, for the extra work is taken from the diastole, the sleeping or resting time of the heart. The blood pressure is generally ten degrees lower in the morning after a good night’s rest; and for this reason, in severe cases, I often advise people to take a whole day in bed once a week, so that this lower pressure may be prolonged for twenty-four hours. The non-medicinal treatment of sclerosis, prophylactic and curative, consists then chiefly in a philosophical, calm mode of life, in a firm restraint of passions, of worry and excitements, in a wise and economic use of brain power, in great moderation in eating and drinking, in giving as much of our time as is possible to fresh air and moderate, unhurried exercise, and lastly to the avoidance of all severe strains on mind or body. Very few of us are able to accomplish all these positive and negative virtues, but as far as in us lies, they should be our rule of life. CHAPTER IV THE MEDICINAL TREATMENT OF SCLEROSIS