(4) The perfect reality and natural, as contrasted with supernatural, character of many wonderful phenomena, both physical and psychical, exhibited in the hypnotic state. On the other hand, much remains for future study; (1) The exact nature of the influence which produces the hypnotic condition is not known. (2) Neither is the nature of the rapport or peculiar relationship which exists between the hypnotizer and the hypnotized subject--a relationship which is sometimes so close that the subject hears no voice but that of his hypnotizer, perceives and experiences the same sensations of taste, touch, and feeling generally as are experienced by him, and can be awakened only by him. (3) Nor is it known by what peculiar process suggestion is rendered so potent, turning, for the time being, at least, water into wine, vulgar weeds into choicest flowers, a lady's drawing-room into a fishpond, and clear skies and quiet waters into lightning-rent storm-clouds and tempest-tossed waves; turning laughter into sadness, and tears into mirth. In dealing with the subject of hypnotism in this hasty and general way, only such facts and phenomena have been presented as are well known and accepted by well-informed students of the subjects. Others still more wonderful will later claim our attention. CHAPTER IV. LUCIDITY OR CLAIRVOYANCE. While there is doubtless a recognized standard of normal perception, yet the acuteness with which sensations are perceived by different individuals, even in ordinary health, passes through a wide scale of variation, both above and below this standard. The difference in the ability to see and recognize natural objects, signs, and indications, between the ordinary city denizen and, for instance, the American Indian or the white frontiersman, hunter, or scout, is something marvellous. So, also, regarding the power to distinguish colors. One person may not be able to distinguish even the simple or primary colors, as, for example, red from blue or green, while the weavers of Central or Eastern Asia distinguish with certainty two hundred or three hundred shades which are entirely undistinguishable to ordinary Western eyes. So of sound. One ear can hardly be said to make any distinction whatever regarding pitch, while to another the slightest variation is perfectly perceptible. Some even do not hear at all sounds above or below a certain pitch; some persons of ordinary hearing within a certain range of pitch, nevertheless, have never heard the song of the canary bird, and perhaps have lived through a large portion of their lives without even knowing that it was a song-bird at all. Its song was above the range of their hearing. Some never hear the sound of the piccolo, or octave flute, while others miss entirely the lowest notes of the organ.