Page:Mind (Old Series) Volume 12.djvu/222

THE PERCEPTION OF SPACE. (ll.) 209 NOTE. The Space of the Blind. The blind man's construction of real space differs from that of the seeing man most obviously in the larger part which synthesis plays in it, and the relative subordination of analysis. The seeing baby's eyes take in the whole room at once, and discriminative attention must arise in him before single objects are visually discerned. The blind child, on the con- trary, must form his mental image of the room by the addition, piece to piece, of parts which he learns to know successively. With our eyes we may apprehend instantly an enormous bird's-eye-view of a landscape which the blind man is condemned to build up bit by bit after weeks perhaps of exploration. We are exactly in his predicament, however, for spaces which exceed our visual range. We think the ocean as a whole by multiplying mentally the impression we get at any moment when at sea. The distance between New York and San Francisco is computed in day's journeys ; that from earth to sun is so many times the earth's diameter, &c. ; and of longer distances still we may be said to have no adequate mental image whatever, but only numerical verbal symbols. But the symbol will often give us the emotional effect of the perception. Such expressions as the abysmal vault of heaven, the endless expanse of ocean, &c., summarise many computations to the imagination, and give the sense of an enormous horizon. So it seems with the blind. They multiply mentally the amount of a distinctly felt freedom to move, and gain the immediate sense of a vaster freedom still. Thus it is that blind men are never without the consciousness of their horizon. They all enjoy travel- ling, especially with a companion who can describe to them the objects they pass. On the prairies they feel the great openness ; in valleys they feel closed in ; and one has told me that he thought few seeing people could enjoy the view from a mountain top more than he. A blind person on entering a house or room immediately receives, from the reverberations of his voice and steps, an impression of its dimensions, and to a certain extent of its arrangement. The tympanic sense noticed on pp. 5, 6 comes in to help here, and possibly other forms of tactile sensibility not yet under- stood. Mr. W. Hanks Levy, the blind author of Blindness and the Blind (London), gives the following account of his own powers of perception : " Whether within a house or in the open air, whether walking or standing still, I can tell, although quite blind, when I am opposite an object, and can perceive whether it be tall or short, slender or bulky. I can also detect whether it be a solitary object or a continuous fence ; whether it be a close fence or composed of open rails ; and often whether it be a wooden fence, a brick or stone wall, or a quick-set hedge. I cannot usually perceive objects if much lower than my shoulder, but sometimes very low objects can be detected. This may depend on the nature of the objects, or on some abnormal state of the atmosphere. The currents of air can have nothing to do with this power, as the state of the wind does not directly affect it ; the sense of hearing has nothing to do with it, as when snow lies thickly on the ground objects are more distinct, although the footfall cannot be heard. I seem to perceive objects through the skin of my face, and to have the impressions immediately transmitted to the brain. The only part of my body possessing this power is my face ; this I have ascertained by suit- able experiments. Stopping my ears does not interfere with it, but cover- ing my face with, a thick veil destroys it altogether. None of the five senses have anything to do with the existence of this power, and the circumstances above named induce me to call this unrecognised sense by the name of 'facial perception'. . . . When passing along a street I can distinguish shops from private houses, and even point out the doors and windows, &c., and this whether the doors be shut or open. When a window consists of one entire sheet of glass, it is more difficult to discover 14