The Senses and the Mind

by Anonymous

From myopia we pass to its opposite, presbyopia, or far-sightedness, (πρέσβυς, old, ὤψ, the eye,) this being a state of vision to which old age is so commonly subject. In presbyopia the refractive powers of the eye are feeble; that is, the rays of light are concentrated into a focus beyond the retina, and, therefore, too far back for the reception by the latter of a definite impression, at the ordinary distance, of normal vision. This condition may result from flatness of the cornea, from an insufficient convexity of the lens, or from a shorter degree than natural of the antero-posterior axis of the eye itself. The pupil is more or less contracted. The far-sighted person either removes the object under examination further than is usual from the eye, or he avails himself of convex glasses, the effect of which is, to increase the refraction, or convergence of the rays of light, before they enter the pupil. Although this condition of the eye is common in elderly or aged persons, we are not to suppose that it is confined to such alone. In aged persons it is one of those signs which bid man prepare for his last mortal change—a change, the premonitory warnings of which are beautifully described in the twelfth chapter of Ecclesiastes. But this affection sometimes occurs in the young; for a time it will remain stationary; but after a certain period, determined by various concomitant influences, it will greatly increase, till at length, indeed, it may be said, "those that look out of the windows be darkened."

Another defect of vision may be next noticed; namely, diplopia, or double vision. This arises from various causes, some of them obscure, and, perhaps, connected with a morbid affection of the base of the brain, such as a tumor pressing on the motor oculi nerve, an inflammatory condition of the brain and its membranes, or a sanguineous or serous effusion involving the origin of the third pair of nerves. It is often the accompaniment of squinting or strabismus, in which, although there is a want of correspondence in the movements or position of the two eyes, the vision of each singly is perfect. Sometimes, however, double vision occurs in one eye only, while, at the same time, there is no disturbance, as far as the harmony of the movements of the two eyes is concerned; occasionally, both eyes are affected by diplopia. In these cases, there must be some irregularity of refraction, either in the cornea or the lens.

M. Prévost, who published an account of his own case, in the "Annales de Chimie et de Physique," 1832, thought that the diplopia under which he laboured might arise from a fracture, bruise, or partial flattening of the lens, or from a separation of its laminæ. Professor Airy and Mr. Babbage both experience the inconvenience of diplopia; in the case of the latter, both eyes are defective, but he can obviate the defect by looking through a small hole in a card, or through a convex lens. "Professor Airy finds that his eye refracts the rays to a nearer focus in the vertical than in the horizontal plane, and he has ingeniously contrived to remedy it by the use of a double concave lens, one surface of which is spherical and the other cylindrical. The spherical surface is to correct the general effect of a too convex cornea; the cylindrical is to converge or diverge those rays at right angles to the axis; while the parallelism of those which impinge upon it in the plane of its axis is unaffected. Thus the focus of the spherical surface will remain unaltered in one plane, but in the other it will be changed to that of a lens, formed by it and a spherical surface of equal curvature with the cylinder. With the aid of a glass of this description, professor Airy could read the smallest print at a considerable distance, equally as well with the defective eye as the sound one. He found that vision was most distinct when the glass was pretty close to the eye, and the cylindrical surface turned from it. With these precautions, he observes, I find that the eye which I once feared would become quite useless, can be used in almost every respect as well as the other."

These are defects in vision which, however distressing, and in themselves, that is, as far as the eye itself is concerned, incurable, may be borne with resignation or remedied by scientific agency. But human beings are often called to still greater trials—to total loss of sight—in other words, to perfect blindness. This calamity results from many causes; for example, the cornea may become so opaque as to be incapable of transmitting rays of light into the interior chamber of the eye; or the crystalline lens, also, may become opaque (cataract;) disease of the iris, attended by closure of the pupil, will produce blindness, as will also paralysis, or loss of energy, in the retina or optic nerve, (Amaurosis or Gutta serena.) Accidents may destroy the powers of the eye, and a flash of lightning may produce Amaurosis; there are, besides, other causes of loss of vision, into which it is not requisite that we should here enter. In certain cases, blindness is congenital, that is, the individual was born blind, but in most instances blindness comes on at various periods of life, subsequent to the age of infancy. Great as is the calamity of blindness, it is not, we think, so heavy an affliction as total deafness. Privation of sight does, indeed, close one avenue leading from matter to mind, but, perhaps, not the most important avenue; we may assume this fact—had Euclid been blind he could still have written on mathematics.

Homer and Milton were both blind, and had Shakspere been blind, the extraordinary creations of his genius would have been what they are—the visions of mighty intellect. An admirably written passage in one of our periodical publications may be here introduced; it proves that blindness closes but a small inlet to the immortal soul: "We are all familiar with many well-authenticated instances of blind persons having attained to a distinguished position both in literature and science. The celebrated Saunderson, who filled the chair of Newton in the University of Cambridge, lost his very eye-balls by the small-pox, when only twelve years old; yet before he was thirty, we find him giving public lectures on optics, explaining clearly the theory of vision, and discoursing admirably on the phenomena of light and colours—thus furnishing by his own extensive acquirements a convincing proof of the extraordinary powers of language, and of the full efficiency of the ear, as an avenue to the mind. The darkness of the blind, such as instances like this sufficiently show, is but a physical darkness; they still possess a ready channel, through which the brightest beams of intellectual light may be freely poured: but the darkness of the deaf mute is a mental and moral darkness; and though he can gaze abroad upon creation, yet it is little more than mere animal gratification that he feels; he looks not through nature up to nature's God, nor does he participate in that high communion which, through the sublimity of her visible language, she holds with the soul of an enlightened being.

"The reason why the blind usually receive from us a deeper sympathy than the deaf, is, perhaps, because the amount of privation borne by the former can be more accurately estimated. We have only to close our eyes, to shut out for a while the glorious light of heaven, in order to conceive how great that privation must be, but we can never for a moment occupy the place of the uneducated deaf and dumb; we cannot shut out our moral and intellectual light; we cannot dispossess our minds of all that language has conveyed there, nor realize by any effort of imagination the melancholy condition of a being grown up in the midst of society, yet deprived of all power of social intercourse; whose mind has never been elevated by a single act of devotion, nor soothed and comforted by a single impulse of religious feeling. Man naturally 'looketh on the outward appearance;' and when we see the bright eye, and the contented, and even joyous aspect of the deaf mute, we forget that we may witness all this in the brutes that perish."

The ear has been happily called the vestibule of the soul, and the annals of the blind who have become illustrious confirm the remark, for they show that few intellectual studies are inaccessible to them. It has even been said, and the assertion has received a kind of universal assent among those who have associated much with the blind, that in certain instances they have a facility which others rarely possess. We would not go so far as Huber, who praised the advantages of blindness, but for which, as he says, he might never have become celebrated; nor as Holman, who has endeavoured to make it appear, that in his blindness he possesses advantages over those travellers who have the use of their eyes, most of whom, as he intimates, though they have the use of these organs in perfection, yet "see not."

Huber and Holman availed themselves of the eyes of others, and in this capability the blind have great advantages over the deaf, for their intercourse with the outward world by means of speech is direct, hence they obtain a knowledge of things, theories, and events, which have passed or are passing, of their condition as men, of the requirements of God, and of the appointed mode of salvation. The deaf and dumb see, indeed, all that passes within their immediate sphere, but, owing to the imperfect and circuitous mode of communication, (by signs,) by means of which alone access to their mind is gained, little definite information relative to things, events, their condition as fallen creatures, the mode of salvation, and regeneration by the influence of the Holy Spirit, can be communicated. They imitate, as we can testify, the actions of those who attempt to enlighten them; they kneel, they raise the eyes, they mimic a solemnity of deportment, and much more, so as to persuade some that they have a clear perception of spiritual truths; but "faith cometh by hearing," and though we would not presume to assign a limit to God in illuminating the darkest mind, yet we doubt whether the soul can in this life become the recipient of the truths and promises of the gospel in all their glorious fulness.

Deaf and dumb persons are generally irascible, impatient, suspicious, and watchful; they creep about stealthily, and take you by surprise; they form habits to which they adhere with unflinching pertinacity, and fret if any trifle molests them. They may attain to a certain degree of cleverness, as the word is usually understood, but we know not any deaf and dumb persons (as far as records go) who have attained to any great degree of eminence, even under circumstances favourable to the development of their powers. But with regard to the blind, they have enriched the arts, the sciences, and literature, by their successful pursuits, and not unfrequently under circumstances of extraordinary difficulty. Viewing both these classes of men as devoid of education, dependent upon themselves for support, and for the enjoyment of life, the blind are physically greater objects of compassion than the deaf, because, without peculiar modes of education, suited to their privation, they cannot obtain a livelihood; but so far as happiness is dependent upon knowledge, (and from this source some of the purest enjoyments arise,) they are nearly on a level with ordinary men. Through the ear they can acquire knowledge of the highest order, but the case of the deaf is the reverse of this. They are not physically so dependent as the blind; for, having the advantage of sight, they may acquire by application the simpler imitative arts, and thus earn a subsistence; but mentally, their great inferiority, their ignorance of themselves, of all that bears upon the concerns of their existence, and upon the condition, order, changes, and phases of things extraneous to themselves, is painfully palpable to every philanthropic observer of his fellow-beings. The light of the eye is theirs, but the light of the mind is exchanged for darkness.