From the earliest ages the apparent power of some men to influence the minds and bodies of others has been known. Certain diseases were said to be affected by the touch of the hand of certain persons, who were supposed to communicate a healing virtue to the sufferer, and these practices were often connected with religious and magical rites. This method of healing was practised in antient times by the Chaldæans, Babylonians, Egyptians, Persians, Hindus, Greeks and Romans. Their priest-physicians are said to have effected cures and to have thrown people into deep sleep in the precincts of the temples. Such influences were at that time held to be due to supernatural power, a belief which was no doubt fostered by the priesthood. In the middle of the seventeenth century an Irishman named Valentine Greatrakes aroused great interest in England by his supposed power of being able to cure scrofula by stroking the patient with his hand. Most of the distinguished scientific men of the day, such as Sir Robert Boyle, witnessed and attested his cures, and thousands of sufferers crowded to him from all parts of the country. Since his time other men have come forward with similar claims, notably one Gassner, a Roman Catholic priest of Swabia, who in the early part of the eighteenth century attracted attention by stating that he could cure the majority of diseases by exorcism. His method had an extraordinary influence over the nervous systems of his patients, who in the end generally confessed themselves cured. [Sidenote: Mesmer’s experiments] In 1766, Mesmer, who was a pupil of Hehl, professor of astronomy at Vienna, and an advocate of the efficacy of the magnet for the cure of disease, met Gassner, and observed that the priest effected cures without the use of magnets and by manipulation alone. This led him to believe that some kind of occult force resided in himself, by means of which he could influence others. He held that this force permeated the universe, and more especially affected the nervous systems of men. In 1778, he removed to Paris, and shortly afterwards the French capital was thrown into a state of great excitement by the fact that human beings could be placed in a state of artificial sleep or trance, which was then called “mesmerism.” Mesmer’s disciples claimed that even painful operations could be performed on patients in this condition without consciousness of pain. [Sidenote: Braid’s researches on hypnotism] [Sidenote: Esdaile operates on hypnotised patients]