Page:Popular Science Monthly Volume 39.djvu/793

Rh. It is a warning which it would be a grave imprudence not to heed.

The elderly man should therefore give up all exercises of speed like running, and all those in which energetic efforts are added to speed, like rowing in matches. We see men of exceptional powers of resistance continuing to practice exercises of speed till they are forty-five years old; but it is well to know how indulgence in championship feats late in life usually ends. Many affections of the heart are consequences of exercises or labors that exaggerate the effort of that organ in men who have reached maturity. The central organ of the circulation can not be subjected without danger to excessive work, when its play is not seconded by the elastic force of an unimpaired arterial system; when it is partly deprived of the re-enforcement which is lent it by these contractile channels, the office of which in the circulation of the blood has been happily described by giving them as a whole the name of the "peripheric heart."

All men who employ animals in work know how their speed falls off with increasing age. Race-horses are withdrawn from the track shortly after they have arrived at the full possession of their force; they are still good for competitions in bottom, and are capable for many years yet of doing excellent trotting service, but they can not run in trials of speed. Man's capacity to run likewise decreases after he has passed thirty years; and the professional couriers who are still seen in Tunis, running over large distances in an incredibly short time, are obliged to retire while still young. Those who continue to run after they are forty years old, all finally succumb, with grave heart affections.

There are some persons who preserve to a relatively advanced age the faculty of enduring violent exercises, and of contesting with young persons in quickness of muscular work. Not long ago two men, one forty-five and the other forty-eight years old, contested in the regattas on the Seine and Marne. Their craft was called the old men's. Few oarsmen continue to row in races after they are thirty-five years old. But those whom we are speaking of, though long past the usual age for retiring, have often gained the prizes which competitors twenty years old disputed for with them. These exceptions, however, do not depreciate the force of the principles we have just explained. They prove that one may be young in spite of his years, and that the chronological age does not always agree with the physiological age. While some persons are in full organic decadence at thirty-five years, some others may not yet, at fifty years, have undergone the modifications of nutrition which are the beginning of old age. The capacity of a man for violent exercises is determined by the more or less complete integrity of the arterial tissues. Men who