In 1860, Dr. A.A. Liébeault (1823–1900) began to study hypnotism seriously, and four years later gave up general practice, settled in Nancy, and practised hypnotism gratuitously among the poor. For twenty years his labours were unrecognised, then Bernheim (one of whose patients Liébeault had cured) came to see him, and soon became a zealous pupil. The fame of the Nancy school spread, Liébeault's name became known throughout the world, and doctors flocked to study the new therapeutic method.
While Liébeault's work may justly be regarded as a continuation of Braid's, there exists little difference between the theories of Charcot and the Salpêtrière school and those of the later mesmerists.
II.—Theory of Hypnotism
The following is a summary of Braid's latest theories: (1) Hypnosis could not be induced by physical means alone. (2) Hypnotic and so-called mesmeric phenomena were subjective in origin, and both were excited by direct or by indirect suggestion. (3) Hypnosis was characterised by physical as well as by psychical changes. (4) The simultaneous appearance of several phenomena was recognised, and much importance was attached to the intelligent action of a secondary consciousness. (5) Volition was unimpaired, moral sense increased, and suggested crime impossible. (6) Rapport was a purely artificial condition created by suggestion. (7) The importance of direct verbal suggestion was fully recognised, as also the mental influence of physical methods. Suggestion was regarded as the device used for exciting the phenomena, and not considered as sufficient to explain them. (8) Important differences existed between hypnosis and normal sleep. (9) Hypnotic phenomena might be induced without the subject having passed through any condition resembling sleep. (10) The mentally healthy were the easiest, the hysterical the most difficult, to influence.
In England, during Braid's lifetime, his earlier views were largely adopted by certain well-known men of science, particularly by Professors W.B. Carpenter and J. Hughes Bennett, but they appear to have known little or nothing of his latest theories. Bennett's description of the probable mental and physical conditions involved in the state Braid described as "monoideism" is specially worthy of note. Not only is it interesting in itself, but it serves also as a standard of comparison with which to measure the theories of later observers, who have attempted to explain hypnosis by cerebral inhibition, psychical automatism, or both these conditions combined.
(a) Physiological.—According to Bennett, hypnosis was characterised by alterations in the functional activity of the nerve tubes of the white matter of the cerebral lobes. He suggested that a certain proportion of these became paralysed through continued monotonous stimulation; while the action of others was consequently exalted. As these tubes connected the cerebral ganglion-cells, suspension of their functions was assumed to bring with it interruption of the connection between the ganglion-cells.
(b) Psychical.—From the psychical side, he explained the phenomena of hypnosis by the action of predominant and unchecked ideas. These were able to obtain prominence from the fact that other ideas, which, under ordinary circumstances, would have controlled their development, did not arise, because the portion of the brain with which the latter were associated had its action temporarily suspended—i.e., the connection between the ganglion-cells was broken, owing to the interrupted connection between the "fibres of association." Thus, he said, the remembrance of a sensation could always be called up by the brain; but, under ordinary circumstances, from the exercise of judgment, comparison, and other mental faculties, we knew it was only a remembrance. When these faculties were exhausted, the suggested idea predominated, and the individual believed in its reality. Thus, he attributed to the faculties of the mind a certain power of correcting the fallacies which each of them was likely to fall into; just as the illusions of one sense were capable of being detected by the healthy use of the other senses. There were mental and sensorial illusions, the former caused by predominant ideas and corrected by proper reasoning, the latter caused by perversion of one sense and corrected by the right application of the others.
In hypnosis, according to this theory, a suggested idea obtained prominence and caused mental and sensorial illusions, because the check action—the inhibitory power—of certain higher centres had been temporarily suspended. These theories were first published by Professor Bennett in 1851.
III.—Hypnotic Induction
The methods by which hypnosis is induced have been classed as follows: (1) physical; (2) psychical; (3) those of the magnetisers. The modern operator, whatever his theories may be, borrows his technique from Mesmer and Liébeault with equal impartiality, and thus renders classification impossible. The members of the Nancy school, while asserting that everything is due to suggestion, do not hesitate to use physical means, and, if these fail, Bernheim has recourse to narcotics.