This is important in relation to various exercises to be described. The art of training for athletic exercises, or laborious exertions, consists in purifying the body and strengthening its powers, by certain processes, which are now to be described. The advantages of it, however, are not confined to pedestrians, wrestlers, or pugilists; they extend to every one: for, were training generally introduced, instead of medicine, for the prevention and cure of diseases, its beneficial consequences would assuredly prolong life, and promote its happiness. Every physiologist knows that all the parts which compose the human body--solids as well as liquids--are successively absorbed and deposited. Hence ensues a perpetual renovation of them, regulated by the nature of our food and general habits. The health of all the parts, and the soundness of their structure, depend on this perpetual absorption and renovation. Now, nothing so effectually as exercise excites at once absorption and secretion. It accordingly promotes all the vital functions without hurrying them, renovates all the parts, and preserves them apt and fit for their offices. It follows, then, that health, vigour, and activity, chiefly depend upon exercise and regimen; or, in other words, upon the observance of those rules which constitute the theory of training. The effect has accordingly corresponded with the cause assigned in this view of the subject, in every instance where it has been adopted; and, although not commonly resorted to as the means of restoring invalids to health, there is every reason to believe that it would prove effectual in curing many obstinate diseases, such as bilious complaints, obesity, gout, and rheumatism. The Ancients entertained this opinion. They were, says a popular writer on medicine, by no means unacquainted with or inattentive to these instruments of medicine, although modern practitioners appear to have no idea of removing disease, or restoring health, but by pouring drugs into the stomach. Heroditus is said to have been the first who applied the exercises and regimen of the Gymnasium to the removal of disease, or the maintenance of health. Among the Romans, Asclepiades carried this so far, that he is said, by Celsus, almost to have banished the use of internal remedies from his practice. He was the inventor of various modes of exercise and gestation, in Rome. In his own person, he afforded an excellent example of the wisdom of his rules, and the propriety of his regimen. Pliny tells us that, in early life, he made a public profession, that he would agree to forfeit all pretensions to the name of a physician, should he ever suffer from sickness, or die but of old age; and, what is extraordinary, he fulfilled his promise, for he lived upwards of a century, and at last was killed by a fall down stairs.