Theoretical Considerations. In the foregoing chapter I (The History Of Hypnotism) have discussed the medical importance of hypnosis, but only as far as its practical application is concerned. But the medical aspect of hypnosis is- not thereby exhausted. Hypnosis has proved of far greater value to medical science, and its indirect assistance to therapeutics has been more valuable than anything produced by its more practical employment As far as the latter point is concerned, hypnosis has led to the development of a new branch of the healing art, psycho-therapeutics, which I shall discuss in the second section of this chapter.

Hypnosis has also proved of importance in medical research. It has thrown light on a source of error in judging the modus operandi of therapeutic measures, which, although not unknown, had been very much underrated. The good results obtained by the use of certain remedies used to be erroneously ascribed to chemical or physical action, whereas it was really suggestion that produced the results. This applies to innumerable therapeutic measures, quite as much to physical methods as to the products of chemical factories. It has also often happened that while one doctor has seen nothing but failure with some drug, another has imagined that it produced brilliant results. As there could be no question of bad faith in such cases, the contradictions they presented necessarily appeared enigmatical until suggestion supplied the key to their solution. We must also bear in mind that a patient's confidence in the advice given him by his doctor very often suffices to bring about the good result, and sets the suggestive action going.

If the same remedy acts differently when administered by different doctors, we are justified in asking the question, to what extent was the difference in its action due to psycho-therapeutic influence? We have to consider that the doctor's conviction of the efficacy of a drug is transferred to the patient. A doctor does not only employ suggestion consciously, but often without either knowing or suspecting that he is doing so. Let us take an example of recent date. Some investigators - Joh. Fred. Fischer, for instance - have asserted that in numerous cases enuresis nocturna in children is brought about by adenoid vegetations. Fischer, indeed, thinks that in the vast majority of cases in which these two symptoms are found to occur together the children cease to wet the bed as soon as the adenoid vegetations are removed. Another doctor - Viktor Lange - disputes the existence of this connection, because in his experience adenoid vegetations had the opposite effect. But when we consider that mental influence plays a most important part in suppressing enuresis nocturna^ and that the doctor's confidence in the method he employs is transmitted to the patient, the raison d'etre of the different results obtained by the operation is at once evident.

We are justified in applying the same criticism to many other methods which are said to cure enuresis nocturna. Maximilian Hirsch asserts that he has obtained brilliant results with Chatelin's epidural injections; but this is contested by Gotzl on the ground of his own contrary experience. When we see that a number of other doctors who have busied themselves with hypnosis - Liebeault, Ringier, Hacklander, for instance - obtain just as good results with hypnotic suggestion as Joh. Fred. Fischer, Maximilian Hirsch, and others do with their methods, may we not take it that suggestion is the common basis of all these methods ?

Many also of the opponents of hypnotism have often underrated the suggestive moment in their remedies in an illogical manner, and have thereby proved that they would have done better to study hypnotism than to oppose it. To pick out only one of these opponents, I mention Mendel, who attempted to introduce the suspension-treatment of tabes dorsalis into Germany. (The attempt is nowadays only of historical interest.) If Mendel had studied the question of suggestion in connection with suspension, there would have been no epidemic of suspension-treatment in Berlin. I may remark, by the way, that as far as my experience goes yohimbin, which was so warmly recommended by Mendel in the treatment of impotence, has no other importance than that derived from the suggestion that accompanies its exhibition. At least, among all the cases that I have treated with yohimbin I have been unable to find a single one in which the effect produced could be traced to the somatic influence of the drug with any degree of probability.

Other opponents of hypnotism, too, who have recommended chemical remedies, have made very similar mistakes because they were unable to form an adequate estimate of the action of suggestion.

We shall, under certain circumstances, be able to avoid falling into any grave error as to new remedies and their action, provided we recognize the significance of suggestion. How comes it that so many remedies are not only widely advertised but even enthusiastically recommended by some doctors, remedies that so soon prove to be useless? How many remedies have been proclaimed hypnotics, how many appetisers, only to be forgotten immediately? And on what does their transient success depend? On suggestion alone, often enough. When a doctor is convinced of the narcotic action of a certain drug, that conviction is readily transmitted to the patient who is under his suggestive influence, and there is therefore no cause for surprise when the remedy does produce sleep. That is why Rosenbach has given a proper way of testing new hypnotics. It is impossible to determine the value of a hypnotic remedy scientifically, when the patient knows he is taking such a remedy. Hypnotism has distinctly proved that. And it is just the same with a number of other remedies, such as purgatives, astringents, anodynes, etc., etc.

All these substances can only be tested as to their true somatic action when every form of suggestive action is scrupulously excluded, and the first requisite in this respect is that the patient should know nothing about the expected effect. The significance of electro-therapeutics has frequently been discussed from this point of view. Mobius has traced many electro-therapeutic effects to suggestion, and, in an exhaustive work on the question, I have expressed the view that, in very many cases at least, the action is mental; in other cases I concluded that the improvement or cure was spontaneous. This view has found both opponents and followers. Whereas Delprat came to the conclusion, on statistical grounds, that electricity made no difference, the cure being no more rapid, other observers have not relinquished the physical influence of electricity in electrotherapeutics. Among such observers are Eulenberg, Sperling, Lcewenfeld, Muller, Laquer, Remak, Wichmann. Eulenburg rieverthejess admitted that in a great number of cases the action was of an essentially mental nature, but that at the same time we must not deny that there is often an action independent of suggestion.