2. _Exercise_.--This is as necessary to health as food. "Only by exercise--physical exercise--can we maintain our muscles, organs and nervous system in proper vigor; only by exercise can we equalise the circulation and distribute the blood evenly over every part of the body; only by exercise can we take a cheerful and wholesome view of life, for exercise assists the digestion, and a good digestion is a sovereign antidote to low spirits; only by exercise can the brain be strengthened to perform the labor demanded of it." [2] No sensible man will try to do without it. If any man does so he will pay the penalty. As to the amount of exercise and the kind of exercise every man must judge for himself. Some, from their occupation, need less than others; the outdoor laborer, for instance, than the clerk who is most of the day at the desk. One man may take exercise best by walking, another by riding, another by following outdoor sports. Athletics, such as football, and cricket, are a favorite form of exercise with the young, and if not followed to excess are most advantageous. The walk in the open air is life to many. But boy or man can never be what they ought to be unless they take exercise regularly and judiciously, take it not to exhaust but to refresh and stimulate. It strengthens the nerve and clears the brain and fits for work. 3. _Rest_.--Man needs a certain amount of repose to sustain his frame in full vigor. Some need more, some need less. We must find out for ourselves what we need and take it. Lack of sleep is especially a great waste of vitality. Here also we must exercise our judgment as to the amount of sleep we require. One needs a great deal; another can do with very little. Early rising, which has been much recommended, is only good for those who go early to bed. If one is compelled to sit up late he should sleep late in the morning. It is no virtue on the part of anyone to get up early unless he has slept enough. _That_ he must do if he is to have health. A man who would be a good worker must see to it that he is a good sleeper; and whoever, from any cause, is regularly diminishing his sleep is destroying his life. Shakespeare has well described the blessing of sleep when he says: Sleep that knits up the ravelled sleeve of care, The death of each day's life, sore labor's bath, Balm of hurt minds, great Nature's second course, Chief nourisher in life's feast. These are but _hints_ in connection with a great subject. A few brief rules may be given of a general character: 1. Take exercise every day in the open air if possible, and make it a recreation and not merely a duty. 2. Eat wholesome food, drink pure water. 3. Let your house and room be well ventilated. 4. Take time enough for sleep. Do not worry. 5. Watch yourself, but not too closely, to find out what exercise, air, diet, etc., agrees with you. No man can be a rule for another.