Of course, the first of these is the most important; and yet, of all things, it seems to be least looked into and understood. We find abundant rules for the government of the tongue and temper; it is a slough into which, John Bunyan hath it, cart-loads of wholesome instructions have been thrown; but how to get and keep that healthy state of brain, stomach, and nerves which takes away the temptation to ill-temper and anger is a subject which moral and religious teachers seem scarcely to touch upon. Now, without running into technical, physiological language, it is evident, as regards us human beings, that there is a power by which we live and move and have our being,--by which the brain thinks and wills, the stomach digests, the blood circulates, and all the different provinces of the little man-kingdom do their work. This something--call it nervous fluid, nervous power, vital energy, life-force, or anything else that you will--is a perfectly understood, if not a definable thing. It is plain, too, that people possess this force in very different degrees; some generating it as a high pressure engine does steam, and using it constantly, with an apparently inexhaustible flow and others who have little, and spend it quickly. We have a common saying, that this or that person is soon used up. Now most nervous irritable states of temper are the mere physics’ result of a used-up condition. The person has overspent his nervous energy,--like a man who should eat up on Monday the whole food which was to keep him for a week, and go growling and faint through the other days; or the quantity of nervous force which was wanted to carry on the whole system in all its parts is seized on by some one monopolizing portion, and used up to the loss and detriment of the rest. Thus, with men of letters, an exorbitant brain expends on its own wreckings what belongs to the other offices of the body: the stomach has nothing to carry on digestion; the secretions are badly made; and the imperfectly assimilated nourishment, that is conveyed to every little nerve and tissue, carries with it an acrid, irritating quality, producing general restlessness and discomfort. So men and women go struggling on through their threescore and ten years, scarcely one in a thousand knowing through life that perfect balance of parts, that appropriate harmony of energies, that make a healthy, kindly animal condition, predisposing to cheerfulness and good-will.