According to Charpentier and Bernheim, the experiments with complementary colours were not more exact; and the same is the case with other experiments of Binet and Fere in colours, from which they drew the conclusion that in suggested perceptions of mixed colours the effect was the same as with real optical images.

We must, consequently, give up any thought of using these experiments when judging of fraud, even when we have to deal with uneducated persons who know nothing of the doubling of images by prisms, or of complementary colours, or of mixed colours.

The phenomenon presented by the pupil of the eye, which Binet and Fere mention, seems more valuable. In suggesting a hallucination - e.g., that of a bird - the suggested approach of the object causes contraction of the pupil, and vice versa. At the same time there is often convergence of the axes of the eyes, as if a real object were present.' But it must be remembered that some persons are able to produce this phenomenon by an effort of will, as Hack Tuke and Budge pointed out long ago. Lefevre quotes the experiments of Beer de Boon, who was able to cause his pupils to contract by imagining that he was in a place where the light was very bright. Piltz, also, has recently published a work on the influence of the will on the pupil-reflex; he lays particular stress on the fact that the idea of light produces contraction, of a dark object dilatation of the pupils. It follows that the phenomenon presented by the pupil of the eye must only be used with great caution in judging of fraud.

Bernheim lays great weight on the analgesia of hypnotic subjects. If a completely analgesic subject is touched with a faradic brush he shows no trace of pain. There are no impostors who could repress the expression of pain under these circumstances, particularly if the contact were unexpected. But we must consider that such a high degree of analgesia is very rare in hypnosis., The anaesthesia of the mucous membranes - e.g., of the membrane of the nose - with regard to ammonia, is to be tested also.

There is no need to say that certain rare phenomena - e.g., secretion of tears and sweat, changes in the heart's action, and organic changes, produced bysuggestion are of the greatest value.

Finally, I wish to call attention to the absence of those movements which I should prefer to call the movements caused by tedium (Langweiligkeit). As is known, a waking man is unable to retain any posture for a long time, even when all his muscles are relaxed.- In the latter case the movements cannot be caused by fatigue of particular muscles; it is rather that when one position is long maintained, a lively feeling of discomfort is produced, that is subjectively felt as tedium. This, it seems to me, leads to certain irresistible movements, the movements of tedium. Their absence is a strong evidence of hypnosis, and I think this an important, but almost entirely unknown, symptom. They are best observed when the subject has been left for some time to himself, without any notice being taken of him.

I have as yet only spoken of such symptoms as take the form of bodily functions; but according to Pierre Janet these bodily symptoms are of much less importance to the question of simulation than the mental ones; the memory in particular. Gurney also held this view. The assumption from which these authors started is that there is loss of memory on waking from hypnosis, and that consequently the subject remembers nothing that has happened during the state. Now, this loss of memory is to be used to decide the question of fraud.

I tell X., whom I have hypnotized, that when he is going to bed he is to dip a towel in warm water and wrap it twice round his throat. When he wakes he seems to remember nothing about what I had said to him while he was hypnotized; upon which I repeat the command, but omit the doubling of the towel. When I ask him what he is to do on going to bed, he answers, "I am to dip a towel in warm water and wrap it twice round my throat." It will be seen that I gave the order differently during and after hypnosis; yet X. repeats the command as it was given in hypnosis.

According to the views of Pierre Janet and Gurney, this would very likely be a case of fraud; for X., who had apparently completely forgotten everything after waking, mentions the one point which was omitted in the second command, and of which he could have no knowledge unless he remembered what had happened during the hypnosis. But must we really consider this a case of fraud ? I believe not, and I appeal to a long series of experiments with perfectly trustworthy subjects, in whom I often observed objective bodily symptoms. A second question to be considered is, How is the proceeding brought about? Here, of course, we must first of all think of the association of ideas mentioned on page 122, by which in this, as in other cases, a hypnotic event may be reproduced after waking. It may happen that the subject adds the word "twice" to a certain extent automatically, and without remarking it; in other cases he may make it consciously, as a previously forgotten idea may be suddenly called into consciousness.

The following case is somewhat similar. I hypnotize X., take hold of his scarf and disarrange it In spite of this he sits quite still, and the hypnosis is undisturbed But directly he wakes he puts his hand to his scarf to straighten it, although he is not supposed to remember what had happened. I would not have taken even this as a proof of fraud without further evidence, for the action in question could be just as well performed automatically, because of the subconscious idea that the scarf was awry.

Such cases naturally make one think of fraud, and the sharper the distinction between the subject's chains of memory, the more are we justified in accepting the hypnosis as genuine. On the other hand, we must not straightway discern a proof of fraud in acts which may possibly have been performed automatically.