This is particularly the case with hypnotics; their whole attention is so fixed - possibly subconsciously - on these signs, that they are able to perceive signs of the existence of which the spectators have no notion. The signs can be made in ways that differ very considerably. One is inclined to look at an object which one is thinking of steadfastly. Any one who has drawn a card and looks at it hard, is inclined to make some corresponding movement with his lips. Strieker mentioned in his work, De la Parole et des Sons interieurs, an articulation faible si peu perceptible que nous ne la remarquons pas d'kabitude. It is from such movements that A., provided he has had practice, can sometimes guess the card that has been drawn, because, for example, B. who has drawn the queen of spades moves his lips as though he were going to say queen of spades. The subject sometimes even whispers gently, as Lehmann and Hansen have pointed out. Similarly, adequate movements are also made with other parts of the body. When anybody thinks steadfastly of a number he is inclined to make the necessary movements with his fingers for writing down that number. I mentioned when dealing with thought-reading that other muscles occasionally participate in such movements.

The whole body is impelled towards the object of which the person is thinking (Tarchanoflf).

Sometimes the signals given are somewhat different. We may observe in cases of thought-reading, that when the reader is taking a wrong direction the person who is concentrating his thoughts, or often some one else who is present, will involuntarily give a sign that at once tells the practised thought-reader that he is on the wrong tack. A loud breath, for example, will do this. A rapid and distinctly audible inspiration will very often tell the thought-reader that he is making a mistake. Also, two Italian authors, Guicciardi and Ferrari, have, as Gley informs us, ascribed an important part to changes in respiration during experiments in thought-transference. In other cases some rougher movement of the body is noticed by the thought-reader if his eyes are not bandaged; but it may quite well be audible.

In any case, the movements just described guide the thought-reader in the right direction, and this may, indeed, occur even when he is not touching the person who is concentrating his thoughts. Now, as a rule the thought-reader generally has his eyes bandaged. As we saw on page 63, it is not necessary that the thought-reader should be able to see when he is in direct contact with the subject, because such direct contact enables him to feel the movements that are made. But, since the involuntary movements just described are also audible, we can understand that the thought-reader can solve the problem that is set him correctly even when his eyes are bandaged and he is not in direct contact with the subject experimented on. Now, as a matter of fact, a whole series of cases has occurred in which thought-reading was accomplished although the reader's eyes were bandaged and he was not in contact with the subject. Consequently, such a case is not necessarily an instance of telepathy, although uncritical experimenters would probably ascribe it thereto. It is very much like the game of hide-and-seek which most of my readers probably played when they were children. One of a number of children is sent to a distance while the others hide something.

The child sent away is then recalled and told to find the hidden object; so long as the child is far off the object it is looking for the others cry out, "cold," when it gets nearer, "warm," and when quite close to it, "hot." Just in the same way the thought-reader, even when his eyes are bandaged and he is not in contact with the person experimented on, finds out whether he is performing his task correctly or not. He can tell from the sighs and changes in the respiration of his audience, and also from other signs, whether he is going in the right direction or not.

It is possible that with certain people tactual sensibility plays a special part - at least in some of the cases. It sometimes happens that the thought-reader finds himself quite close to the person who is concentrating his thoughts, and that the latter stretches out his hand while the thought-reader's is close to his hand or arm. Now, supposing the subject makes some movement with his hand or whole body in the direction of the object to be discovered - it is easy enough to show that such movements may be considerable - and supposing the thought-reader possesses a very fine sense of temperature, then we can readily understand that the thought-reader's hand should tell him the direction in which the movements are being made. The amount of resistance offered by the air may also have something to do with this. There are persons who are quite able to perceive in the dark whether they are near a wall or any other solid substance. The resistance of the air to movements is different near a wall to what it is in the middle of a room (cf. p. 99). Consequently, it is possible for the thought-reader to tell from the resistance of the air the direction in which the subject's hand is moving, and this fact helps him to solve the problem that has been set him.

Nevertheless, it is probable that less weight should be laid on this circumstance than on perception by means of the sense of hearing.

Lively discussions have recently taken place as to whether the blind possess a special sense or not. One author, Ludwig Cohn, who is himself blind, has asserted that such is the case; while Brandstaeter, an instructor of the blind, has denied its existence. A special point that has been raised in this discussion is how it comes about that the blind are quite able to orientate, or take their bearings as to the position of things about them, either in a room or in the street: they can even distinguish whether they are close to a wall or not. Some ascribe this to the sensation produced by the pressure of the atmosphere, which differs when the surrounding space is clear from what it would be in the proximity of a wall. At all events, the sensibility may be so delicate that a blind person shut in a room can tell the size of it or the position of the furniture in it without touching anything. Opinions differ as to whether normal individuals can accomplish as much. Important authorities, Zell and Hauptvogel, for example, have answered this question in the affirmative.