Exercise is a point of absolute necessity. To the weak it is a pain to take it; and if they have any inclination to melancholy or dejection of spirit, it is not easy to determine them to motion; and yet nothing is more apt to augment all the evils that proceed from weakness, than inactivity; the fibres of the stomach, of the intestines, of the vessels, are lax; the humors every where stagnate, because the solids have no longer the strength to impress on them the necessary motion: thence are generated lodgments of matter, choaked up passages, obstructions, extravasations; coction, nutrition, the secretions, do not proceed; the blood remains aqueous, the strength diminishes, and all the symptoms of the disorder increase. Exercise prevents all these evils, by augmenting the force of the circulation; all the functions execute themselves as if there existed in the body a real strength for it, and this regularity of the functions does not fail soon to give it, so that the effect of motion is to supplement the vital forces, and to restore them. Another of its advantages, independent of the augmentation of circulation, is its enabling one to enjoy an air always new. A person that does not stir, soon corrupts the air which surrounds him, and becomes noxious to him: whereas a person in action is continually changing it. Motion may often supply the place of remedies, but all the remedies in the world cannot supply the place of motion. The fatigue of the first days of attempting it, is a rock against which the faint heart of many of the sick is apt to split; but if they had the courage to conquer this first obstacle, they would soon be experimentally sensible, that to this case especially it is that that proverbial saying is truly applicable, _Il n’y a que les premiers pas qui coûtent_: “It is only the first steps that are hard to take.” I have been myself astonished at seeing to what a degree those who had not been disheartened at the first, acquired strength by exercise. I have seen persons fatigued with one turn in a garden, arrive, in a few weeks, at being able to take a walk two leagues, and be the better after it. The exercise of walking on foot is not the only favorable one. For persons extremely weak, for such as have a complaint of their bowels or breast, riding on horseback is even better: but in a still greater weakness, the motion of a carriage, if not too easy an one, is preferable. When the weather does not allow of going out, some means of motions should be contrived, in the house, some not too laborious occupation, or some exercise of play; such, for example, as the battledore and shuttle-cock, which diffuses through the whole body an equable motion.