In my account of the water-diviner I suggested that his dissociated stream was especially trained to pick up indications that are not observed by his ordinary self. The study of the hypnotic state shows that our senses sometimes work better when freed from the control of the consciousness, so that the subject is able to see or hear or feel what is unobserved by the ordinary man. He possesses a hyperaesthesia such as we see in a sleeping dog who wakes at the approach of a footstep inaudible to the human ear and recognises whether it belongs to friend or stranger. A similar alertness and its opposite can be seen at work in ordinary sleep. The mother is roused by the slightest whimper of her babe, whilst louder noises pass unheard; but the person who, with the best intention of breaking a bad habit, has an alarm clock by his bedside, may neglect its call for a few mornings and end by entirely failing to hear it. The hyperaesthesia belonging to the unconscious is shown in other conditions than hypnosis and ordinary sleep. Jung quotes experiments[13] of Binet, who says: 'According to the calculations I have been able to make, the unconscious sensitiveness of a hysteric is on some occasions fifty times more acute than that of a normal person.' [Footnote 13: _Analytical Psychology_, p. 25.] Dr. Hurst, writing on War Neuroses,[14] says: 'In one severe case true hyperacusis was present, and Captain E. A. Peters estimated that the patient heard sixteen times more acutely than the average normal individual. It was possible to carry on a conversation with him by whispering in one corner of the ward when he was lying in the opposite corner, although men with normal hearing who were standing half-way between in the centre of the room could not hear a word of what was whispered.' [Footnote 14: _British Medical Journal_, September 29, 1917.] I myself knew a war-strained patient who, as a result of terrifying experiences, had a dread of aeroplanes and could not only hear a plane long before his comrades but could tell at once by the hum of the engine whether it was British or German. In other respects his hearing was no better than his neighbour's. Another case under my observation was that of a nervous lady with a fear of draughts. Whilst secluded in her bedroom she claimed to be affected when far-away doors were open, and showed a most uncanny and accurate knowledge as to whether they were open or shut, though this knowledge was probably derived from the sense of hearing and not from any sensitivity to heat or cold. The word 'hyperaesthesia' is used to denote an excessive acuity of our senses. The examples quoted above refer to the sense of hearing; but other senses, such as touch and sight, may be similarly sharpened. Binet's experiments were carried out on the sense of touch.