To achieve fortune, to judge well and command one's fellow-men, to foretell and control the future, to be wise in worldly lore, are natural objects of human desire; but still another is essential to happiness. Whether we attempt to procure these good fortunes by going early to bed and early to rise, or by more occult procedures, we wish to be healthy as well as wealthy and wise. The maintenance of health and the perpetuity of youth were not absent from the mediæval occultist's search, and formed an essential part of the benefits to be conferred by the elixir of life and the philosopher's stone. A series of superstitions and extravagant systems are conspicuous in the antecedents and the by-paths of the history of medicine, and are related to it much as astrology is to astronomy, or alchemy to chemistry; and because medicine in part remains and to previous generations was conspicuously an empirical art rather than a science, it offers great opportunity for practical error and misapplied partial knowledge. It is not necessary to go back to early civilizations or to primitive peoples, among whom the medicine-man and the priest were one and alike appealing to occult powers, nor to early theories of disease which beheld in insanity the obsession of demons and resorted to exorcism to cast them out; it is not necessary to consider the various personages who acquired notoriety as healers by laying on of hands or by appeal to faith, or who, like Mesmer, introduced the system of animal magnetism, or, like some of his followers, sought directions for healing from the clairvoyant dicta of somnambules; it is not necessary to ransack folk-lore superstitions and popular remedies for the treatment of disease; for the modern forms of "irregular" healing offer sufficient illustrations of occult methods of escaping the ills that flesh is heir to.