Improveability of the Sense of Touch. — The mental participation in the phenomena of tactile sensation is further rendered obvious by the improvement in discriminating power which results from continual attention to its indications. Of this we have examples in the case of certain artisans, whose employments re quire them to cultivate their tactile discrimina tion ; thus, the female silk-throwsters of Bengal are said to be able to distinguish by the touch alone twenty different degrees of fineness in the unwound cocoons, which are sorted ac cordingly; and the Indian muslin-weaver con trives, by the delicacy of his touch, to make the finest cambric in a loom of such simple construction, that European fingers could at best propose to make a piece of canvas in it. The improvement in tactile discrimination is more especially seen, however, in those indi viduals whose dependence upon it is increased by the loss or deficiency of other senses ; and especially by blindness, congenital or ac quired. Whilst it is doubtless to be attri buted, in great part, to the concentration of the attention and of the powers of recollec tion and comparison upon the sensations which are brought (as it were) to the mind, it may not seem altogether improbable that the improvement may in part depend upon an increased development of the tactile organs themselves ; resulting from that augmented nutrition which would be the natural con sequence of the frequent use of them, and of the increased flow of blood that seems to take place towards any part on which the attention is continually fixed. Certain it is, that many blind persons can not merely obtain as defi nite and accurate conceptions of the form, surface, &c., of objects over which they ra pidly pass their hands, as others could only derive from the long and painstaking examin ation of them by their tactile organs ; but they can discriminate minute differences, of which those who have not specially cultivated this faculty remain quite unconscious, even when their attention is pointedly directed to their discovery. The process by which the blind learn to read from books printed in an ele vated type for their special use, affords an interesting illustration of the nature of the improveability of the proper sense of touch. On first making the attempt, the learner needs to use a large type; and even although (to a person who has previously enjoyed his sight), the visual form of each letter may be well known, yet considerable experience is required for the ready recognition of the tactile form of each separate letter. After this step has been gained, the individual becomes able, by a fur ther period of diligent application, to recog nise the combination of letters in syllables and words, without forming a separate idea of each letter, just as we see to take place in the child learning to read by eyesight ; and the pupil in time acquires the power of read ing line after line, by passing the point of the finger consecutively over each, with consider able rapidity. Now when this power has once been thoroughly acquired, it is found that the size of the type may be gradually diminished, so that at last it may be reduced to one but little larger than that of an ordi nary folio Bible, which is read at least as rapidly as the words can be spoken.* As an instance of the readiness and nicety of dis crimination which is frequently acquired by those who are chiefly dependent upon this sense for their knowledge of the outward world, we may advert to the well-known case of Laura Bridgman ; who, though destitute of sight, hearing, and smell, is able to recognise individuals with whom she has once been well acquainted, by feeling their hands, even after a long distance of time. It is related of Carolan, the celebrated blind Irish bard, that on accidentally grasping, at an interval of some years, the hand of a female to whom he had been formerly attached, he at once exclaimed, with strong emotion, " This is the hand of Bridget Cruise." A lady, who became blind, and soon afterwards deaf and dumb, in conse quence of an attack of confluent small-pox, and whose case is recorded in the Annual Register for 1758, seems to have very speedily acquired a remarkable exaltation of the sensibility she retained. Like James Mitchell (see SMELL, p. 702.), she could distinguish strangers from acquaintance by the smell ; but she required the further help of the touch to distinguish one friend from another. " When they came in, they used to present their hands to her as a means for making themselves known. The form and the warmth of the hand generally furnished the differences which she distin guished; but sometimes she would span the wrist and measure the fingers. A lady with whom she was well acquainted, coming in upon a very hot day after having walked a mile, presented her hand as usual ; she examined it longer than ordinary, and seemed to doubt to whom it belonged; but at length she I think it is Mrs. M. ; but she is warmer to-day than I ever felt her before: "- Of this lady it is positively affirmed that she was able to distinguish colours by the touch. "A lady, who was nearly related to the sufferer, having an apron on, which ac cording to the fashion of the time, was em broidered with silk of different colours, asked her if she could tell her what colour it was ; and after applying her fingers attentively to the figures of the embroidery, she replied that it was red, blue, and green ; but whether there were other colours in the apron, the writer of the account does not remember. The same lady having a pink ribbon on her head, and being desirous still further to satisfy her curiosity and her doubts, asked her what colour that was ? After feeling it for some time, her cousin answered that it was a pink colour. This answer was the more surprising, as it showed that she was not only capable of distinguishing different colours, but different shades of the same colour."* It is probable that in this and similar cases, the difference of hue is indicated by some diffe rence of surface, which becomes appreciable to a refined touch. Of course, it can only be to a person who has once enjoyed sight, and who can therefore form ideas of colour, that such ideas could be suggested by the sense of touch ; and a new set of associations must be formed by habit between the tactile qualities of the surface, and the visual conception called up by its designation. Those who have been born blind must be utterly incapable of forming any such conceptions, and distinc tions of colour can be to them nothing more than names ; yet even such have been able to discriminate by the touch between stuffs of different hues, which were similar in other respects. That such a power should be attained seems the less difficult of belief, when it is ;borne in mind that all colour depends upon the molecular arrangement of the par ticles of the surfaces of bodies ; so that there is no great improbability—much less an im possibility— in the asserted discrimination of these by a touch rendered delicate by con stant practice, and by the habit of attending to its minutest indications. It is well known
that Dr. Saunderson, the celebrated blind pro fessor of mathematics at Cambridge, not only acquired a very accurate knowledge of medals, but could even distinguish genuine medals from imitations, more certainly than most connoisseurs in full possession of their senses ; and this power must have depended on pecu liarities of their surface, too minute to be ap preciated by an ordinary touch, and not dis tinguished by the sight.
Not only does the sense of touch, in its simplest form, undergo this remarkable exalta tion, but also the muscular sense, which is em ployed in combination with it in the acquire ment of information respecting the forms, di mensions, distances, &c. of objects. Of this, the case of the lady just cited affords an apt illustration : " To amuse herself in the mourn ful solitude and darkness to which she had been reduced, the sufferer took to working with her needle; and it is remarked that her needlework was uncommonly neat and exact. Among many other pieces of needlework pre served in her family, was a pincushion which could scarcely be equalled. She used also sometimes to write ; and her writing was executed with the same neatness and precision as her needlework ; the characters were very pretty, the lines were all even, and the letters placed at equal distances from each other : hut the most extraordinary circumstance was, that she could by some means discover where a letter or a word had been omitted, and would place the caret under and the word over, in the right place."* This fact is obviously analogous to those formerly related, in refer ence to the exaltation of the muscular sense in the state of somnambulism. (See SLEEP, p. 694.) It is by the accurate estimates which they are thus enabled to form, that we find the blind able to learn various handicraft arts, performance on musical instruments, &c. &c., which they practice with great success ; cabi net-making, turning, and even watch-making, seem to be within the capacity of such as have a mechanical turn ; but the greatest perfec tion of this sense is shown by those who have succeeded in modelling and sculpture. Of these, Giovanni Gonelli, sometimes called Gambasia, from the place of his birth, deserves special mention. He lost his sight at the age of twenty, and remained for ten years in that state, ignorant of the very elements of sculp ture. But, on a sudden, the desire of making a statue came upon him ; and having handled in every way a marble figure representing Cosmo de Medici, he formed one of clay so extremely like, that it astonished all who saw it. His talent for statuary soon developed itself to such a degree, that the Grand Duke Ferdinand of Tuscany sent him to Rome to model a statue of Pope Urban which he also rendered a very striking likeness of the original. He afterwards executed many others with equal success ; amongst these, a marble statue of our Charles I. It is re lated that the Duke of Bracciano, who had seen him at work, doubted much that he was completely blind, — and in order to set the matter at rest, he caused the artist to model his head in a dark cellar. It proved a striking likeness. Some, however, objecting that the duke's beard, which was of patriarchal ampli tude, had made the operation of producing a seeming likeness too easy, the artist offered to model one of the duke's daughters, which he accordingly did ; and this also proved an ad mirable likeness. Dr. Guillee, who details the preceding case in his " Essai sur ('Instruc tion des Aveugles," mentions also the more recent case of M. Buret, whom he calls ‘‘ one of the most able sculptors of the academy; " who became blind at the age of twenty-five, but was not thereby deterred from pursuing with much success, the course of life which he had previously chosen. It is easy to be con ceived that a blind man might thus model or chisel accurately under the guidance of his touch, so far as mere form is concerned ; but it has been thought difficult to understand how he could thus discriminate and embody that expression, which has been supposed to be intangible* When it is remembered, how ever, that expression must at last depend upon niceties of form, and can only be imitated by the sculptor who is under the guidance of his sight, by a minute attention to these niceties, the difficulty altogether disappears. The blind sculptor cannot form an idea of the expres sion of his model, as seen by the eyes of others; but he may reproduce that expression with complete success, by perfectly imitating the form which exhibits it ; just as he may study and understand the laws of optics, without having ever seen the faintest ray of light. The study of natural history might have been supposed to be beyond the reach of the blind, in consequence of the difficulty of distinguish ing specimens by the touch alone ; yet there have been examples of complete success in this pursuit. Thus of John Gough it is re lated, that "from an early age he showed a very decided taste for zoology ; and in time he began to enlarge his knowledge of organic bodies by extending his researches from the animal to the vegetable kingdom. To bo tanical pursuits all the time he could spare from the necessary studies of the school was most assiduously devoted ; and as his ardour in cultivating this branch of science was never relaxed, he soon conquered most of the dif ficulties which the want of sight opposed to the gratification of this taste, and was even tually able to discriminate and arrange with great accuracy the plants that came under his notice. His usual method of examining a plant was by applying the tip of his tongue to its several parts. Ordinary plants he could easily and readily distinguish by the touch of his fingers. To evince the power of discri mination and strength of memory, which could alone have enabled him to take an interest in this pursuit, it is mentioned, that towards the end of his life a rare plant was put into his hands, which he very soon called by its name, observing that he had never met with more than one specimen of it, and that was fifty years ago."* A case of the same kind has been long under the writer's observation ; the subject of it being a gentleman who became blind from amaurosis soon after the age of twenty. His attention having been directed to geology and conchology, he gradually acquired a very complete knowledge of shells both recent and fossil ; being not only able to re cognise every one of the numerous specimens in his own cabinet, but also to mention the nearest alliances of a shell previously unknown to him. He has occupied himself, moreover, in freeing his fossil shells from their matrix, with a hammer and chisel, knife, &c. ; and has frequently done this with a perfection that could scarcely be surpassed, rarely injuring the specimen with his tools, and generally clearing it completely from its incrustation, where this was practicable. In this way he has succeeded in forming a very valuable col lection of the fossils of the interesting locality in which he resides.