Изображения страниц
PDF
EPUB

poles excluded from the light, while they grew in size, did not change into frogs; other tadpoles, subjected to precisely the same treatment in every respect excepting the exclusion of light, went through the proper metamorphosis at the usual time. Dr. Edwards also observes, that those nations among whom the fashion of dress leaves a considerable surface of the body exposed to the action of light, exhibit forms more gracefully rounded and of better muscular development than are to be found elsewhere. Miners, on the other hand, and those who live much in the dark, are generally misshapen, and of "pale and leaden" hue.* Anhamia (want of blood) is a consequence of their mode of living. According to M. Dufau's description, the condition of the blind bears much resemblance to this. He compares their appearance to that of pale etiolated plants which have grown up in the shade. He speaks of their imperfect sanguification, and their awkward attitudes and gestures. He further points out that of the blind those who have some imperfect visual sense are more vivacious and active than those whose darkness is total. Of the latter class, those whose blindness is due to paralysis of the optic nerve, or affection of the brain, are less inclined to movement than those in whom the visual apparatus merely is disordered. These circumstances seem to show that, independently of its effect as the cause of vision, the action of light on the eye is a powerful and healthy stimulus, through the optic nerve, of the entire nervous system, and that its action upon the surface of the body, though less effectual, is real and beneficial. When either of the factors is diminished or impaired,when the light acts on a feebler organisation, or less light finds access to an organisation of equal vigour, the result is a diminished nervous force and muscular activity.

While we are speaking of the physical influence of light, we may refer to a question connected with this subject which has been made a matter of controversy among the blind themselves; viz. whether those who are totally destitute of vision have any sense whatever of the presence or absence of the luminous fluid. M. Knie, who has translated into German, with notes of his own, the treatise of M. Dufau, affirms that, "in spite of his state of complete blindness, he has a feeling of the light." M. Rodenbach, who also is blind, affirms, on the other hand, that the blind man whose eye has altogether wasted away can have no sensation except of the degree of heat, moisture, &c., which coincides with the presence of the luminous ray. M. Zeune is of the same opinion. M. Dufau seems to incline to the opposite view. The question was first started by Diderot, who relates the following incident of Saunderson :

* See Encyclopædia Britannica, 8th edition, art. “Light."

"It is said that, during some astronomical observations which were one day being made in a garden in his presence, the clouds which from time to time hid the disk of the sun from the observers occasioned a change in the action of the rays upon his face, which was sufficiently sensible to him to enable him to mark the moments which were favourable for observations, and the contrary. You may perhaps suppose that some agitation capable of informing him of the presence of light, but not of the presence of objects, occurred in his eyes. I should have thought so too, if it were not certain that Saunderson had lost not only sight, but the organs of sight. Saunderson, therefore, saw by means of his skin."

As clouds would intercept heat as well as light, this instance is not conclusive. M. Dufau relates others; but they do not necessarily show more than that the blind are cognisant of a difference between day and night. This, however, may be due to the change of temperature, and of atmospheric conditions, rather than to any distinct and immediate perception of the luminous fluid itself. Nevertheless, considering that the solar rays which convey heat are different from those which convey light, and that the necessity of the latter to healthy organic life, vegetable and animal, is clearly established, it may very well be the case that their action upon the nerves of the skin, of which the effect probably is to quicken and exalt the vital activity, is attended with a peculiar feeling, which, like most vague and obscure sensations, escapes those who have a better clue to the presence of the object from which it proceeds. The physical (as distinguished from visual) sense of the absence of light, in a slackened energy and torpor of the entire organisation, is perhaps expressed in the complaint which Milton transfers from himself to the hero of the Samson Agonistes:

"Since light so necessary is to life,

And almost life itself,

why was the sight

To such a tender ball as the eye confined,

So obvious and so easy to be quenched?

And not, like feeling, through all parts diffused,
That she might look at will through every pore?
Then had I not been thus exiled from light,
To live a life half-dead, a living death,
And buried; but oh, yet more miserable,
Myself my sepulchre, a living tomb!"

From the influence of blindness on the physical constitution generally, we pass to the effects of the absence of vision upon the remaining senses. Its well-known tendency to increase their range and quicken their susceptibility is expressed in the oftenquoted lines of Rochester, which tell us,

"That if one sense should be suppressed,

It but retires into the rest ;"

from which the inference would be that the perception of colours, which alone is proper to sight, is possible without it. The meaning intended to be conveyed is, however, clear and true, that the knowledge of outward objects and their laws, which the seeing gain by the examination of one set of their qualities, the blind may acquire as certainly and accurately by attention to another. This part of our subject has been abundantly illustrated by anecdotical writers. It is the most piquant and interesting; and it would be unfair to our readers to omit it, and to confine them entirely to those more abstract and drier topics which have preceded and will follow it. Indeed, the intellectual and moral characteristics of the blind as a class are so intimately connected with, and are to a large extent so clearly the consequence of, the peculiarities of their organisation and sensibility, that some consideration of the latter is essential to the understanding of the former.

Taking the several senses in succession, we begin, for several reasons, with the Muscular Sense, or the feelings attending the muscular motions; the claims of which to rank as a sixth sense are now pretty generally recognised by writers on physiology and mental science. The new-born infant, in obedience, it may be probably conjectured, to an impulse from within, to a spontaneous discharge of the nervous force proceeding from its centres in the brain and spinal ganglia to the muscles, moves and tosses his limbs long before he shows any sign of being affected by impressions from without. These movements are attended with certain feelings peculiar to them, often of a very pleasurable kind, as is shown by the delight taken by children in active games, by the young of animals in their gambols, and by men of vigorous health, "muscular Christians" and others, in athletic exercises. To be incapable of this pleasure, to have a distaste for the exertions which procure it, is justly deemed a proof of a disordered or languid organisation. We have seen that this is, as a rule, the case with the blind. The chief physical enjoyments connected with the muscular system are, for them, those of conscious repose, resembling probably the agreeable sensations of rest after moderate fatigue. A slight feeling of fatigue may be considered as their ordinary condition, in regard at least to this part of their nature. Their delight in bodily inaction, or in slow and measured movements, is like that of the weak eye in a shaded light, or its preference of the milder green rays to "the common light of day." It is easy to see how this state of feeling reacts upon the intellectual character. Rapidity of mere physical motion produces a certain rapidity and intensity of mental action. Many instances of this might be adduced. The student is often compelled to sti

mulate the sluggish flow of thought by a rapid walk up and down his chamber. Douglas Jerrold is said to have composed in this way. The violent gestures of the popular orator are often quite evidently assumed, in the first instance, to rouse in him the vehemence which they seem to express, and of which they may afterwards become the unconscious expression. Slow movements, on the other hand, have a contrary effect; they calm and soothe rather than stimulate. What is true of them in their action on special occasions, is of course equally true of them as a life-long influence. It is in harmony with these observations that the blind, as a class, are seldom characterised by that rapidity and intensity of mental action, that keenness of penetration, which pierces at once to the very heart of a matter,-that vivida vis animi which is the characteristic of the highest genius. Their intellects are in general cautious, calm, deliberative, slow, distinguished rather by soundness than by brilliancy. The force which they apply is accumulative rather than instantaneous. We do not mean that all these qualities are to be attributed exclusively to the single source which we have indicated, or even that all the said qualities are to be found in all blind people. What is asserted is, that the tendency of the condition of the muscular sensibility in the blind is to produce the characteristics acknowledged, though with many exceptions and in various degrees, to belong to them as an order. The fact that their attachments are generally of a calm and equable kind, formed on judgment and "right reason,' rather than upon those inexplicable attractions which so often bind others together; the infrequency with which they seem to give way to strong impulses of affection, and a certain want of geniality and expansiveness which has often been noted in them, -may also, no doubt, in part be attributed to the same cause. Vividness of sensation, and clearness of perception, exist always in an inverse ratio; or, as Sir William Hamilton, to whom we believe the first statement of this law of mind is due, expresses it: "Above a certain point, the stronger the sensation, the weaker the perception; and the distincter the perception, the less obtrusive the sensation." Vision, which is the clearest of our modes of objective perception, is ordinarily attended with scarcely any subjective feeling; taste and smell, which give us hardly any knowledge of objects, appeal forcibly to the passive sensibility. Intense light dazzles the eye, excessive sound deafens the ear; and both prevent clear perception. The feebleness of the muscular sensations in the blind does not therefore by any means. imply indistinctness in the corresponding perceptions. These are, among others, the discrimination of degrees in the weight, in the hardness and softness, the elasticity and inelasticity, of objects, as estimated by the resistance they offer to pressure,

[ocr errors]

and the consequent muscular tension needed to withstand or overcome this resistance. Without, perhaps, being peculiar to this sense, the cognition of space, and its several modes and diversities that is to say, the magnitude, the distance and direction (which, taken together, gives the position) of objects, their form, &c.-may no doubt be gained by consciousness of differences in the sweep and contraction of the muscular movements. The nicety of discrimination acquired by the blind in regard to these qualities has received many illustrations. Diderot says of the celebrated blind man of Puesseaux, a visit to whom occasioned his Lettre sur les Aveugles: "He appreciates with wonderful accuracy the weights of bodies and the capacities of vessels; and he has made of his arms balances so exact, and of his fingers compasses so well tested, that on occasions on which this sort of static is called into play, I would always back our blind man against twenty who see.' The lady patient of Sir Hans Sloane, who became blind, deaf, and dumb, through confluent small-pox, manifested the same fineness of muscular sensibility. "To amuse herself in the mournful and perpetual solitude and darkness to which her disorder had reduced her, she used to work much at her needle; and it is remarkable that her needlework was uncommonly neat and exact. . . . . She used also sometimes to write; and her writing was yet more extraordinary than her needlework; it was executed with the same regularity and exactness; the character was very pretty, the lines were all even, and the letters placed at equal distances from each other: but the most astonishing particular of all, with respect to her writing is, that she could by some means discover when a letter had by some mistake been omitted, and would place it over that part of the word where it should have been inserted, with a caret under it."*

[ocr errors]

This last-mentioned circumstance requires stronger faith or stronger testimony than we possess to convince us of the fact. There is nothing improbable in the other assertions. The blind in general, indeed, are obliged to have recourse to a special apparatus in writing, to prevent the pen from wandering over the paper. But the case of the American girl, Laura Bridgman (blind, deaf, and dumb), as well as that of Sir Hans Sloane's patient, proves that the muscular sense may be brought to a degree of perfection which enables it to dispense with artificial aids. Mr. Dickens, in his American Notes, says of Laura Bridgman, who wrote in his presence: "No line was indicated by any contrivance; but she wrote straight and freely." Laura Bridgman appears to have used one set of muscular movements to watch over, and correct if needful, the set in action. "I Encyclopædia Britannica, original edition, art. "Blind.”

« ПредыдущаяПродолжить »