Susceptibility.—As to the number of people who are susceptible to hypnotism, there are great differences of opinion. Liebault declared that practically every one is susceptible in the hands of a patient operator. In a carefully made series of cases his failures were less than three per cent. Van Rentergehem and Van Eeden, in a series of over 1,000 persons, failed only with fifty-eight, or little more than five per cent. Schrenk-Notzing's statistics, collected from many countries, seem to show that only about six per cent. were uninfluenced. Bernheim, at Nancy, was not nearly so successful as Liebault, his master, and his failures amounted to twenty-five per cent. at the beginning and at least twenty per cent. later. I remember that when I was at the Saltpêtrière fifteen years ago, they were inclined to discount the enthusiasm of the Nancy school with regard to the value and significance of hypnotism. They insisted that probably not more than one out of two of the persons presenting themselves at a nervous clinic could be hypnotized to the extent that is ordinarily associated with the word—could be brought beyond the drowsy stage. There are other workers in the subject who have insisted that not more than one out of three ordinary individuals can be so [{160}] deeply hypnotized as to exhibit the ordinary symptoms. These symptoms consist of complete neglect of surroundings and absolute absorption in the suggestions of the operator.
Some people can be hypnotized to the extent of being thrown into sleep and yet walk and talk under the absolute control of the operator. These are so-called somnambules, the class of persons who are exhibited by professional hypnotizers who want to attract popular attention, and, indeed, the class usually exhibited by physicians before medical societies, and even by professors before their classes. This extreme susceptibility is, however, quite rare. Even the most ardent advocates of hypnotism and of the susceptibility of humanity to it do not claim that more than one in ten of average individuals can be influenced to this degree. There are milder degrees of hypnotism than this, until we reach a state in which all the patients feel is a certain dreamy sense of well-being and a heaviness of the eyes, with a readiness to respond to suggestions. Most people who think of the somnambulistic stage as representing hypnotism would not consider these latter to have been at all subjected to the hypnotic state.
Repeated Efforts.—As to this question of susceptibility, much depends on how often the operator has tried to hypnotize the particular subject, for susceptibility develops with repeated trials, not only where there is a manifest impression at first, but also where there is not. It is not uncommon to find that a patient who cannot be brought at all under the influence of hypnotism in the first or second or third trial, will, at the fifth or sixth trial, yield to the suggestion to go into a hypnotic sleep. A dozen unsuccessful efforts may be followed by the development of a very satisfactory hypnosis. Those who have practiced hypnotism much tell of having tried a score or even two score of times before finally bringing on a hypnotic condition. Dr. J. Milne Bramwell, one of the English authorities on hypnotism, tells the story [Footnote 20] of having tried sixty or more times to hypnotize patients before finally succeeding. It is this persistence that enables successful hypnotic operators to accomplish results where less confident physicians fail. It is also the frequency of trial that makes all the difference in the statistics as to the susceptibility of patients to hypnotism in the hands of different individuals. There must be the confidence of the patient in the physician's power to hypnotize, but, above all, there must be the physician's own confidence in his power to bring on the hypnotic sleep so that he tries and tries again, even to seventy times.
[Footnote 20: "Hypnotism. Its History, Practice and Theory," by J. M. Bramwell, 2nd edn. London, The De la More Press, 1906.]
ANIMAL HYPNOTISM
The hypnotization of animals shows that only a very low grade intelligence is needed for the production of this state. The famous experiment of Father Kircher with the hen, which any one may repeat at any time, is a good illustration. The fascination exerted upon birds by snakes is another familiar example. The bird is paralyzed with terror at the sight of the snake, and so cannot escape from its enemy, fairly glueing its eyes on the terrifying object, and thus loses power to control its wings. Stories of snake [{161}] fascination are usually told as if the eye of the snake attracted the bird, who thereupon proceeded to approach the snake. These are, however, doubtful stories. The paralysis of motion seems to be the main effect. The rabbit is affected in nearly the same way. There is a tremor of horror in anticipation, and then the animal stands perfectly quiet, though ordinarily he would be quite able to escape, while its enemy approaches. The underlying mechanism is evidently a concentration of attention, which completely precludes the possibility of the exertion of any spontaneous energy except that involved in the one act of watching the awful object.
DANGERS OF HYPNOTISM
There are many and various opinions of the dangers of hypnotism. Some of those who have given it a fair trial have insisted on its dangers. Some of those who have had very large experience have declared emphatically that there is no danger at all. Occasionally it has seemed that such a declaration must be considered as having been dictated by such intensity of interest as sometimes leads men to overlook the darker side of things with which they are much occupied. Certain moral aspects of hypnotism are at least dubious, and, it must be admitted, present opportunities for abuse. There are certain dangers connected with its effect upon nervous patients, and especially with its influence upon character, that have become more and more clear in recent years. Dr. John K. Mitchell, in his "Self Help for Nervous Women," a series of familiar talks on economy in nervous expenditure, [Footnote 21] has dwelt on certain of these dangers of hypnotism for nervous patients in a passage that deserves to be recalled. As a representative of a school of thought that is worthy of special regard from American physicians his expressions must carry weight:
[Footnote 21: Philadelphia, Lippincott, 1909.]
The greatest danger of all is the use of hypnotism in any form or degree, a two-edged sword, capable indeed of usefulness, but more capable of harm. After years of study, beginning with too easy an approval of it, hypnotism, whether called by that name or by the unsuitable one of suggestion, has been laid aside by the medical profession as a means too dangerous for ordinary use, involving great risk of deterioration of character in the subject if often repeated, and putting a terribly tempting tool in the hands of the user, fascinating in the ease with which it can produce superficial and temporary good results and equally capable of being used for harmful ones.
A susceptible person, once hypnotized, is more and more easily thrown into the hypnotic state until even the slightest hint suffices to bring about the condition. It is not necessary for the hypnotization to go so far as deep sleep; this more advanced stage is indeed seldom required, and to say that persons are not hypnotized because they are not put into a sleep or a trance shows ignorance of the subject.
I am not asserting that very slight degrees of the hypnotic condition are as dangerous as the deeper, but I do say that all degrees of it are dangerous to the integrity and healthy action of the subject's nervous system. The danger of harm increases with every repetition of the hypnotization.
In suggestible, that is, over-susceptible, individuals, who are almost universally neurotic persons, to fix the eyes on a small point, especially a bright one, sometimes even to fix the mind on the one idea of going into the hypnotic state (mild or deep), is enough without further intervention from any one to put them into that state.