Bodily vigor is the basis of mental and physical health. Strength is power, and the instinctive love of invigorating exercise manifests itself in the young of all but the lowest brutes. The bigot who undermines the health of his children by stinting their outdoor sport as “worldly vanity,” and “exercise that profiteth but little,” is shamed by animals who lead their young in races and trials of strength. Thus the female fox will train her cubs; the doe will race and romp with her fawn, the mare with her colt. Monkeys (like the squirrels of our northern forests) can be seen running up and down a tree and leaping from branch to branch, without any conceivable purpose but the enjoyment of the exercise itself; dogs run races, young lions wrestle and paw each other in a playful trial of prowess; even birds can be seen sporting in the air, and dolphins on the play-fields of the ocean. In nearly all classes of the vertebrate animals the rivalry of the males is decided by a trial of strength, and the female unhesitatingly accepts the victor as the fittest representative of his species. Normal children are passionately fond of athletic sports. In western Yucatan I saw Indian girls climb trees with the agility of a spider-monkey, and laughingly pelt each other with the fruits of the Adansonia fig. The children of the South-sea Islanders vie in aquatic gymnastics. Spartan girls joined in the foot-races of their brothers, and by the laws of Lycurgus were not permitted to marry till they had attained a prescribed degree of proficiency in a number of athletic exercises. Race-running and wrestling were the favorite pastimes of young Romans in the undegenerate age of the republic; and, in spite of all restraints, similar propensities still manifest themselves in our school-boys. They pass the intervals of their study-hours in competitive athletics, rather than in listless inactivity, and brave frosts and snowstorms to get the benefit of outdoor exercise even in midwinter. They love health-giving sports for their own sake, as if instinctively aware that bodily strength will further every victory in the arena of life.