Few persons are ambidextrous. Many more might use the hands with equal skill, if they would. Even so simple an operation as putting on a coat, using the wrong arm first, or buttoning a vest with the other hand, is awkward for most persons, and quite difficult to many. The best time to begin is in childhood, but, even if, when first learning the use of tools, the left hand is often made to do the work of the right, the exchange will prove restful to the overworked hand, and the symmetrical development of both sides of the body will be preserved. A skillful teacher of music, in a private school near Philadelphia, suffered a partial paralysis of his right arm, which prevented its use for several years. This necessitated the increased use of the left hand, which resulted in its increased skill and power. Several years later, he removed to the South, where the warmer climate gradually restored the use of the right arm. By this time, the left hand had become almost as skillful as the right had been, and the severe affliction proved to be a blessing in disguise. =Brain Workers.=--The brain workers are usually men of sedentary habits. To no class is exercise so important. Without it, some part of the human machinery is almost certain to get out of order. It may be the stomach or lungs, the liver or kidneys, the head, or eyes, or throat. There is a lack of perfect action of one or more of the parts, a clogging of the organs of digestion, or circulation, or respiration. This physical clogging at once affects the mental work, dulling the thinking powers, and often rendering their efforts futile, and making the complete cessation of labor necessary. Headaches and indigestion are among the first ailments resulting from a lack of exercise. A brisk walk of twenty minutes or half an hour is often sufficient to dispel a headache. The exercise flushes the parts most actively engaged, and so depletes the brain. The same exercise stimulates the action of the lungs, makes better blood, quickens the activity of the other organs, and so tones up the whole man. A young man, whose Christian zeal prompted him to devote all his spare time to religious work, ignoring the demands of health, broke down, and after a prolonged sickness, followed by a slow and tedious convalescence, was heard to remark, “Well, this experience has taught me one thing; the Lord has no use for a sick man.” Had this young man taken a reasonable amount of exercise, he would have lost no time from his business, would have accomplished vastly more work for the religious organizations to which he belonged, and would have saved himself the pain, suffering, and expense of his sickness.