The transition from the antecedent to the present status of hypnotism was accomplished in the main by two factors; by the precise determination, according to rigidly scientific methods, of the physiological and psychological characteristics of the hypnotic state, and by the advocacy of its claims and the further development of its sphere of influence, on the part of professional men of ability and acknowledged standing. The mischievous and erratic associations of mesmerism, as also of hypnotism, were difficult to outgrow. Unjustifiable skepticism and neglect were the natural consequences of extravagance, perversion, and charlatanism. Even the repeated and verifiable production by hypnotic means of anæsthesia sufficient for serious surgical operations, was ignored; partly, perhaps, because of the discovery of ether, which turned the interest in anæsthetics into new channels. The legitimate and progressive investigations of such as Braid, Liebault, Azam, Durand de Gros, and others, were only fitfully and sparsely recognized. As late as 1874 Dechambre, in his Medical Encyclopedia, declares that all the phenomena rest upon self-deception and delusion, and that the condition does not exist. But beginning with the third quarter of the century the attitude rapidly changed. Richet (1875) published an important paper in an authoritative physiological journal, in which he again established by scientific methods the reality of the hypnotic condition. In this he wrote, "It requires considerable courage to speak aloud the word somnambulism. The stupid credulity of the masses and the pretensions of certain charlatans have brought the thing itself as well as the name into such disfavor that there are but few men of science who do not look disparagingly upon any communication on the subject." The advocacy of Charcot (1878) and his demonstrations at the Salpêtrière finally succeeded in gaining the day; and in 1882 the ban placed upon academic discussions of this subject was lifted by the reception on the part of the Academy of Science of a memoir by Charcot on hypnotism. The extensive series of studies instigated by him at the Salpêtrière, and carried on with marked ability and success by those who in some measure drew their inspiration from the field of inquiry which he inaugurated; the recognition which he secured for the presentation of studies upon hypnotism before learned societies; the far-reaching influence of his authority,--all contributed to the acceptance of hypnotism as a scientific fact, and the inclusion of its study within the circle of the sciences. It should be carefully noted, however, that the period (which, to connect it with the name of but one of its representatives, may be called the period of Charcot), though marked by important extensions of our knowledge of hypnotic phenomena, was in essence a period of reinstatement. All the essential and fundamental discoveries had been made and forgotten,