Power of Mind and Body increased by Concentration of Attention and Energy. - Suppression of One Faculty tends to increase the Development of Others. - Concentration of Mind on One Idea in Somnambulism, and Performance of Tasks impossible when awake. - Some Tragical Results of Natural Somnambulism. - Artificial or Hypnotic Somnambulism may be turned to Therapeutic Purposes. - Natural Sleep may pass into Hypnotic Sleep, and vice versa. - The Faculties may be aroused and intensified in Hypnotic Somnambulism.

I have endeavoured to show how much the imagination (in its widest sense) may have to do with the health of mind and body; and I shall now try to point out that the effects of ' directed consciousness' are greatly increased under certain conditions, when the mind is so withdrawn from the consideration of all extraneous ideas as to be absolutely concentrated upon one object.

We have seen how concentration of mind-faculty, whether self-induced or brought about by some shock to the system, or some powerful external influence, can modify functions, and both produce and cure disease - sometimes gradually, but often, in the case of shock or sudden and overpowering influence, with a rapidity which seems almost miraculous.

We all know, and frequently by our own experience, that mind-concentration, brought about by some strong motive, will enable us to perform mental or bodily actions of which we would generally be incapable. Through it a man will achieve feats of strength far beyond his apparent muscular power, or will go boldly through dangers from which he would shrink if he paused to consider probable consequences. Or he will, in a limited time, execute a prodigious amount of intellectual work, possibly of such startling excellence that he himself, in after-moments of less intensity, will be amazed at his own performance. Of course, concentration, if sustained at such a pitch, would in time be the ruin of mind and body; but we know that it is a necessary factor in the accomplishment of all great things, and that there can be no success in life for those who cannot command it to a moderate degree.

As a rule, happily, the organic functions which carry on life are purely automatic; but, as we have seen, it is possible to concentrate the attention upon them, and so affect their operation, sometimes beneficially, but far more commonly with detriment to the health of mind and body. Those bodily movements over which we have full control are also generally performed automatically. Under ordinary circumstances, we give no conscious thought to our steps in walking, to the motion of our hands while at work; these are nearly as automatic as healthy breathing. So likewise, in a general way, is the operation of the senses. We see, hear, feel without any effort of our will, unless some special motive impels us to exercise it. We concentrate our minds upon sight when we strive to see a minute, or indistinct, or distant object; and upon hearing when we listen for a faint or eagerly-expected sound. If such concentration is continuously brought to bear upon any sense, it will in time convey automatically the more intense impression which has been exceptional. Thus, in savages and in travellers and settlers in wild or dangerous regions, the senses of sight and hearing are far more keen than in those who live under civilization. The senses of touch and hearing become exquisitely fine in the blind.

A blind man will sometimes hear sounds which are absolutely inaudible to ordinary ears, and recognize objects by touch as correctly as most people can by eyesight. Some blind persons seem, through concentration, to have developed a sense of space. On entering a room they can tell whether few or many persons are present; they can guess with wonderful accuracy the size and shape of an enclosed place, and have a curious power of avoiding any obstruction, such as an article of furniture, which may be in their way. * Laycock relates how blind persons are able to recognize their friends by touch alone, and cites several instances in which, from a subtle comparison of form, smell, texture, etc., they have been able to form correct ideas about colour. In the well-known case of Caspar Hauser, who was brought up in solitude and darkness, all the senses were of extraordinary acuteness, so that he could distinguish colours in the dark and hear sounds inaudible to other people. The more recent example of Laura Bridgman must be familiar to most readers. Though blind, deaf, and dumb from infancy, she possessed great intelligence, and kept up close relationship with the outside world through the development of the sense of touch.

She was able to recognize her friends after months of absence by the touch of their hands. The history of another American blind, deaf, and dumb girl, Helen Keller, recently told by herself in her autobiography, is, however, the most striking of all these stories, and shows how the highest education may be won through the exercise of one sense only, when the brain-power of genius is existent but latent. She has graduated in honours at the University, and speaks several modern and ancient languages. She is able to follow conversation accurately and rapidly by keeping her finger on the speaker's lips and noting their movement. Professor Binet investigated the case of a hysterical girl who, when blindfolded, could discriminate and describe the relieved surface of an unknown coin when pressed against the skin. He reckoned that she possessed in this respect fifty times the normal amount of sensitiveness. Hyperaesthesia of the special senses is not of uncommon occurrence in hysterical subjects; and I have met a young lady whose nights were rendered miserable by the noise made by billiard-balls used on a table at least fifty yards away, and quite inaudible to ordinary persons.

Smell is almost a lost sense with a large proportion of civilized mankind, but in many hysterical and neurotic subjects it is developed to an even painful extent, so that persons and things are readily distinguished by their odour. Such sensory hyperaesthesia is readily produced in the hypnotic state by suggestion, and explains many supposed instances of clairvoyance. Dr. Ralph Vincent relates how at Oxford he used to hypnotize undergraduate friends and make them pick out gloves belonging to different persons just as a dog does; and in the Brighton experiments of the Society for Psychical Research, subjects hypnotized with their eyes open were able to select cards from the pack quite indistinguishable in their waking state.

* Most people have probably noticed that closing the eyes will, for the moment, render the hearing and touch unusually acute. Any sense may be intensified by mind-concentration, as in the case of tea and wine tasters and of professional buyers of raw silk, who develop an unerring capacity of judging its quality by touch.