A peculiar species of phenomena is that in which a letter, or word, or object, is eliminated from the consciousness of the patient. For instance, A B is told that on awaking he is to write certain words, say 'Alexandra Palace,' without the letter a. He will do this, and in so rapid and business-like a manner that the observer (who had better try to do the like) must be convinced of the genuineness of the experiment. Or he is forbidden to use the pronoun I, when he will be at extraordinary pains to avoid the word, and will not once be betrayed into employing it, though, as in the case reported by Max Dessoir, he may use its equivalent in some foreign language. The subject may be wide awake and perfectly reasonable in all other respects, but this idee fixe is firmly implanted in his mind, though he is absolutely unaware of its presence. If shown his copy in which the letter a or the pronoun I is missing, he will see nothing wrong about it, and the delusion remains until he is told to return to his usual state, when the absurdity of the thing will be at once apparent, and he will perhaps deny having written the incorrect words or sentences.

* According to Richet (op. cit.), the normal sleep of young children is almost somnambulic, and in support of this theory he instances the case of his little boy, aged five, who remains profoundly asleep when his father goes in at night to caress him, but who murmurs a welcome and returns the embrace. The next morning the child is unconscious of what has passed. It must be the experience of all observers that not only in such a matter, but in other everyday occurrences, a child is frequently in a condition resembling hypnosis, and this perhaps explains the fact that children are such satisfactory subjects for hypnotic treatment. The balance of the faculties has not yet been attained, and thus readjustment is easily effected.

Several varieties of aphasia may be functionally induced by suggestion. The subject may be rendered incapable of uttering a sound (complete motor aphasia), or can be made to reply to every question by a meaningless formula, as in some of the pathological cases cited by Trousseau and by Gowers. He may be conscious or unconscious of the absurdity, just as in the pathological entity, and the condition may be modified in various directions. He may, for instance, be unable to pronounce the letter e, but able to write it, or vice versa. We know that aphasia may occur from functional causes, as from a strong emotion, when one is rendered speechless by terror, indignation, or overwhelming joy or surprise; * and the induced aphasia of hypnotism seems to resemble this variety rather than that which sometimes occurs in the course of typhoid fever and from reflex disturbances. The subject is well worth the attention of physiologists, and its study may throw light on some morbid conditions connected with speech. The differentiation is very much finer than anything of this nature to be seen in disease, and requires correspondingly fine analysis. Sir W. Gowers remarks on the deficiency of facts and the redundancy of theories connected with this subject.

Hypnotic experiments may help to increase the former and prove or disprove the latter *

* Dr. Ireland (op. cit., p. 273) cites a case of sudden gift of speech under the influence of exciting emotion. A well-known merchant in London had a son about eight years of age who was perfectly dumb, so that all hope of his ever speaking had long been abandoned. The boy was intelligent, and had no other infirmity. During a water-party on the Thames the father fell overboard, and the hitherto dumb boy cried out: ' Oh, save him, save him !' From that moment he spoke nearly as well as his brothers, and afterwards became an active partner in his father's business.

Violent emotion may cause other effects than transient loss of speech. Charcot † gives the case of an intelligent man who, after a violent paroxysm of rage, lost the memory of visual impressions. Though he could see objects, they all appeared strange to him, and he could not recognize his friends, nor even his own face in the glass. Injury to certain parts of the brain, especially the lower parietal lobe, may induce this 'psychical' or 'mind' blindness, and this condition can be exactly simulated by suggesting it to a sufficiently sensitive hypnotized subject. The association between the visual centre and the higher intellectual centres in which memory resides is inhibited in both cases .‡

That suggestion acts by partially or wholly inhibiting the perceptive centres seems demonstrable; but how it does this cannot at present be explained. There is, of course, great scope for self-deception in hypnotic experiments; but if subjects of proved integrity are chosen (hysterical women and young boys are not so trustworthy as intelligent artisans), and if they are kept in ignorance of the phenomena which the operator desires to obtain, simulation need hardly be feared. Negative hallucination, as described on p. 3S7, is a complex condition which I cannot explain, as some would do, by calling it mere clever acting. Sometimes, indeed, I suspect unconscious simulation on the part of the patient, as in the case of E. H------, who, when told not to see Dr. F------, carefully avoided looking in his direction, and refused to answer when he spoke to her, except once, when she looked puzzled, and answered him while looking towards me.

* By hypnotic suggestion reading may be rendered impossible (alexia). The subject may also be made incapable of writing (agraphia), and can even be prevented from expressing himself by signs (amimia). Sewing, drawing, and indeed every action, may be tabooed by the same means. (See ' Der Hypnotismus,' by Dr. A. Moll, p. 92, Berlin, 1889.)

† Quoted in Landois and Stirling's ' Physiology.'

‡ Partial or complete loss or impairment of all the special senses may be induced in a similar way by suggestion; e.g., the subject may be rendered unable to perceive the odour of violets, while noticing all other scents, or not to see red, while other colours remain distinct. The hypothesis that certain cells of the cortical perceptive centres are differentiated in the process of evolution to react to the special stimulus of certain sounds, odours, or colours, and that these are inhibited, is a tempting one.