Page:Mind (Old Series) Volume 12.djvu/223

 210 w. JAMES : than one composed of a number of small panes. From this it would appear that glass is a bad conductor of sensation, or at any rate of the sensation specially connected with this sense. When objects below the face are perceived, the sensation seems to come in an oblique line from the object to the upper part of the face. While walking with a friend in Forest Lane, Stratford, I said, pointing to a fence which separated the road from a field, ' Those rails are not quite as high as my shoulder '. He looked at them, and said they were higher. We, however, measured, and found them about three inches lower than my shoulder. At the time of making this observation I was about four feet from the rails. Certainly in this instance facial perception was more accurate than sight. When the lower part of a fence is brick- work, and the upper part rails, the fact can be detected, and the line where the two meet easily perceived. Irregularities- in height, and projections and indentations in walls, can also be dis- covered." According to Mr. Levy, this power of seeing with the face is diminished by a fog, but not by ordinary darkness. At one time he could tell when a cloud obscured the horizon, but he has now lost that power,, which he has known several persons to possess who are totally blind. These effects of aqueous vapour suggest immediately that fluctuations in the heat radiated by the objects may be the source of the perception. One blind gentleman, Mr. Kilbume, an instructor in the Perkins Institution in South Boston, who has the power spoken of in an unusual degree, proved, however, to have no more delicate a sense of temperature in his face than ordinary persons. He himself supposed that his ears had nothing to do with the faculty until a complete stoppage of them, not only with cotton but with putty on top of it, by abolishing the perception entirely, proved his first impression to be erroneous. Many blind men say immediately that their ears are concerned in the matter. Sounds certainly play a far more prominent part in the mental life of the blind than in our own. In taking a walk through the country, the mutations of sound, far and near, constitute their chief delight. And to a great extent their imagination of distance and of objects moving from one distant spot to another seems to consist in thinking how a certain sonority would be modified by the change of place. It is unquestionable that the semi-circular canal feelings play a great part in defining the points of the compass and the direction of distant spots, in the blind as in us. We start towards them by feelings of this sort ; and so many directions, so many different-feeling ' starts '. The only point that offers any theoretic difficulty is the prolongation into space of the direction, after the start. We saw on p. 206 that for- extradition to occur beyond the skin, the portion of skin in question and the space beyond must form a common object for some, other sensory surface. The eyes are for most of us this sensory surface ; for the blind it can only be other parts of the skin, coupled or not with motion. But the mere gropings of the hands in every direction must end by surrounding the whole body with a sphere of felt space. And this sphere must become enlarged with every movement of locomotion, these movements gaining their space-values from the semi-circular-canal-feelings which accompany them, and from the farther and farther parts of large fixed objects (such as the bed, the wainscotting or a fence) which they bring within the grasp. It might be supposed that a knowledge of space acquired by so many successive discrete acts would always retain a somewhat jointed and so to speak granulated character. When we who are gifted with sight think of a space too large to come into a single field of view, we are apt to imagine it as composite, and filled with more or less jerky stoppings and startings (think, for instance, of the space from here to San Francisco), or else we reduce the scale to an intuitively manageable one, and imagine how much