I have dwelt the longer, in this section, on the _general_ principles of diet, because I am of opinion that whatever is true, on this subject, in regard to the diet of children, soon after weaning, is equally, or nearly equally applicable to the whole of childhood, youth, manhood and age. It is not true that one period of life, and one mode of employment, demands a diet essentially different from that which is demanded at another period, and in other circumstances; provided always, that the individual is in health. Occasional instances of the kind, there may be; but they are not numerous. The digestive powers of the young are more nearly as strong as those of the adult than is usually admitted, and they are much more active. They require a less quantity of food, undoubtedly; and they should be fed at shorter intervals. But as a general rule, what is best for them, as regards its quality, at three years old, is best for them at thirty; or, should they live so long, at ninety. I repeat it; there is very little difference in the nature of the food required ever after teething. Let me not be understood as saying that the strong, and the robust, and the active cannot digest food which the weak, and enervated, and indolent cannot. Undoubtedly they can. But this does not prove that they _ought_ to do it. It does not prove that their strength and vigor were not given them for other purposes than to be expended on the poorer substances for food, when they might have better. Nor is it true, as often pretended, that the hard laborer needs either more food, or that which is of a stronger quality, just in proportion to the severity of his labor. The man or the child who labors moderately, just sufficient for the purposes of health, and labors with his hands in the open air, needs rather _more_ food than the indolent or the sedentary, or those who labor to excess; but not that which is of a stronger quality. It is he who labors to excess--if any difference of quality were required at all--who should eat milder food, as well as less in quantity. Some physicians there are who tell us that all mankind would live longer, as well as be more healthful, if they ate nothing but bread, and drank nothing but water. It may be so, but I do not believe it. Water, as I shall show hereafter, is indeed the only appropriate drink; but I do not believe that bread, even after the second year, is in all cases and circumstances the best food. Besides that the experiments of Majendie and other physiologists go a little way--though not far, I confess--to prove that animals generally, (and if so, why not man, as well as the rest?) thrive best with some degree of variety in their food, it seems to me more in accordance with the general intentions of the Creator, so far as we can discover what they are.