HYDROMANCY is another superstition which has incidentally led to the discovery of the medicinal virtues of many mineral waters; a belief in the divining nature of certain springs and fountains is, perhaps, the most ancient and universal of all superstitions. The Castalian fountain, and many others amongst the Grecians, were supposed to be of a prophetic nature; by dipping a fair mirror into a well, the Patræans of Greece received, as they imagined, some notice of ensuing sickness or health. At this very day, the sick and lame are attracted to various hallowed springs; and to this practice, which has been observed for so many ages and in such different countries, we are no doubt indebted for a knowledge of the sanative powers of many mineral waters. There can be no doubt, moreover, but that in many cases, by affording encouragement and confidence to a dejected patient, and serenity to his mind, whether by the aid of reason or the influence of superstition, much benefit may arise; for the salutary and curative efforts of nature, in such a state of mind, must be much more likely to succeed; equally evident is it, that the most powerful effects may be induced by the administration of remedies which, from their disgusting nature, are calculated to excite strong and painful sensations of the mind.[29] Celsus mentions, with confidence, several medicines of this kind for the cure of Epilepsy, as _the warm blood of a recently slain Gladiator_, or a certain portion of _human_, or _horse flesh_! and we find that remedies of this description were actually exhibited, and with success, by Kaw Boerhaave, in the cure of Epileptics in the poor-house at Haerlem. The powerful influence of confidence in the cure and prevention of disease, was well understood by the sages of antiquity; the Romans, in times of pestilence, elected a dictator with great solemnity, for the sole purpose of driving a nail into the wall of the temple of Jupiter—the effect was generally instantaneous—and while they thus imagined that they propitiated an offended deity, they in truth did but diminish the susceptibility to disease, by appeasing their own fears. Nor are there wanting in modern times, striking examples of the progress of an epidemic disease having been suddenly arrested by some exhilarating impression made upon the mass of the population. In the celebrated siege of Breda, in 1625, by Spinola, the garrison suffered extreme distress from the ravages of Scurvy, and the Prince of Orange being unable to relieve the place, sent in, by a confidential messenger, a preparation which was directed to be added to a very large quantity of water, and to be given as a specific for the epidemic; the remedy was administered, and the garrison recovered its health, when it was afterwards acknowledged, that the substance in question was no other than a little colouring matter.