LESSON XXIII. THE FOOD OF LIFE. "To the soul time doth perfection give, And adds fresh lustre to her beauty still; And makes her in eternal youth to live Like her which nectar to the Gods doth fill. The more she lives, the more she feeds on truth; The more she feeds, the strength doth more increase; And what is strength, but an effect in youth Which, if time nurse, how can it ever cease?" SIR J. DAVIES. A horse can live, and do a good deal of dull work, on hay; but spirit and speed require grain. There is no self-supplied, perennial fountain within the animal that enables him to expend more in the way of muscular power than he receives in the way of muscular stimulus and nourishment. Food, in its quality and amount, up to the limit of healthful digestion, is set over against, and exactly measures, under ordinary circumstances, the quality and amount of labor of which a horse is capable. So, a cow can live on straw and corn-stalks; but it would not be reasonable to suppose that she would give any considerable amount of milk upon so slender a diet. We do not expect rich milk, in large quantities, to be yielded by a cow that is not bountifully fed with the most nutricious food. The same fact attaches to land. We cannot get out of land more than there is in it; and having once exhausted it, we are obliged to put into it, in fertilizers, all we wish to take from it in the form of vegetable growths. Wherever there is an outgo, there must be an equal income, or exhaustion will be the inevitable consequence. The principle which these familiar facts so forcibly illustrate is a very important one, in its connection with human life. We cannot get any more out of human life than we put into it. All civilization is an illustration of what can be accomplished by feeding the human mind. All barbaric and savage life is an illustration of mental and moral starvation. The differences among mankind are the results of differences in the nourishment upon which their minds are fed. Eunice Williams, who was taken captive by the savages of Canada a hundred and fifty years ago, was the daughter of a most godly minister, of the old Puritan stamp; but a very few years of savage feeding made her a savage. Her mind was cut off from all other varieties of nourishment, and could only tend to savage issues. She kept a knowledge of her history, and many years after her capture revisited her home, accompanied by her tawny husband; but no persuasions could call her from her savage life and companionship. The conversion of men from heathenism to Christianity and Christian civilization is accomplished by introducing new food into their moral and mental diet. "A change of pastures makes fat calves," we are told; and any one who has noticed the effect upon an active mind of its translation from one variety of social and moral influences to another, will recognize the truth of the proverb.