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330 as we have seen, to become mischievous in some shape: and that is function the second. To him it is a matter of indifference for a time whether the quantity of material which his food supplies to the body is greater than his ordinary daily expenditure demands, because his energy and activity furnish unstinted opportunities of eliminating the surplus at all times. But the neglect to adjust a due relation between the "income" and the "output" can not go on forever without signs of mischief in some quarter. A tolerably even correspondence between the two must by some means be maintained to insure a healthy condition of the body. It is failure to understand, first, the importance of preserving a near approach to equality between the supply of nutriment to the body and the expenditure produced by the activity of the latter, and, secondly, ignorance of the method of attaining this object in practice, which give rise to various forms of disease calculated to imbitterembitter [sic] and shorten life after the period of prime has passed.

Let it be understood that in the matters of feeding and bodily activity a surplus of unexpended sustenance—here referred to as "the balance"—is by its nature exactly opposite to that which prudent men desire to hold with their bankers in affairs of finance. In this respect we desire to augment the income, endeavoring to confine expenditure within such limits as to maintain a cash balance in our favor to meet exigencies not perhaps foreseen. But, in order to preserve our health when that period of blatant, rampant, irrepressible vigor which belongs to youth has passed away, it is time to see that our income of food and our expenditure through such activity as we have constitute a harmonious equality, or nearly so. It is the balance against us of nutritive material which becomes a source of evil. And it is a balance which it is so agreeable and so easy to form, and which often so insidiously augments, unless we are on our guard against the danger. The accumulated stores of aliment, the unspent food, so to speak, which saturate the system are happily often got rid of by those special exercises to which so large a portion of time and energy is devoted by some people. It is to this end that men at home use dumb-bells or heavy clubs, or abroad shoot, hunt, and row, or perform athletic and pedestrian feats, or sweat in Turkish baths, or undergo a drench at some foreign watering-place—all useful exercises in their way, but pursued to an extent unnecessary for any other purpose than to eliminate superfluous nutrient materials, which are occasioning derangements in the system, for which these modes of elimination are the most efficient cure, and are thus often ordered by the medical adviser. But as we increase in age—when we have spent, say, our first half-century—less energy and activity remain, and less expenditure can be made; less power to eliminate is possible at fifty than at thirty, still less at sixty and upward. Less nutriment, therefore, must be taken in proportion as age advances, or rather as activity diminishes, or the individual will suffer. If he continues to consume the same abundant