CHAPTER IV.. Observations on the Agency of the Senses, Relative to the Union

OBSERVATIONS ON THE AGENCY OF THE SENSES, RELATIVE TO THE UNION BETWEEN MIND AND MATTER; AND ON THE OCCASIONAL IMPERFECTION OF THE BODILY ORGANS OF THE SENSES, WITH THE RESULTS DEPENDING THEREUPON.

That the organs of the senses communicate with the mind, through the mediation of certain mysterious filaments, or thread-like bodies, termed nerves, cannot be denied; but the manner in which this communication takes place, the process by which mind receives information from matter, and the subtle operations which enable matter to transfer impressions to mind, are points around which, as it appears to us, the great Author of our being has thrown an impenetrable veil. It is true, that, in consequence of certain discoveries relative to what the older writers termed "the nervous fluid," discoveries which almost go to prove that the "fluid" is of an electric or electro-magnetic nature, a bold theory has been promulgated, namely, that these electro-magnetic currents not only give an impress to the mind or soul, but are in turn influenced by the agency of the immaterial principle, and that thus the communication between mind and matter is carried on; in fact, that the link which unites body to mind is a mysterious agent, which (its name is of little importance) cannot be recognised as belonging to the material world. Where revelation leaves a subject untouched, it is, we humbly think, allowable to theorize from facts which science has laid open; but let us remember that, however we may incline to a theory which seems consonant to science, a knowledge of the limitation of our intellectual powers should lead us to cultivate a spirit of humility and candour. It is something to approximate towards truth; let us, then, be content to leave much for a future revelation which science on this earth can never unfold before us.

The foregoing observations may be regarded as a slight introduction to a passage on the connexion between the mind and body, well worthy of especial consideration: "In considering the connexion between the mind and the body, it is of the highest importance always to remember that the mind, or rather the being which thinks and wills, is the active agent. The body, with all its beautiful and wondrous adaptations, only supplies the means of perception and of acting. Nerve-matter is the evident medium and instrument of the being that perceives and acts through it. Physiologists appear to have demonstrated that an imponderable principle, akin to electricity, is evolved in the nervous system, and that currents of this kind are constantly traversing the different sets of nerves, according to their office and function, either as the medium of sensation, volition, or of vegetative life. There is, in short, an action going forward in all the nerves and their centres similar to the electro-magnetic, and, consequently, every nerve is polarized. The soul appears to operate upon these electro-magnetic currents, and to be impressed by them. The imponderable energia passing in these currents, is apparently the medium between the soul and the more palpable materials forming the body. This may be inferred from the fact, that whatever alters the force of these currents, alters the condition of the mind in relation to the body. Thus, the arrest of the current in a nerve, subservient to voluntary muscular action, whether by chemical or mechanical means, prevents the mind from exercising will in the use of the muscle, with which the nerve experimented on is connected. The same occurs, also, in the like case with any nerve through which we obtain sensation of the presence of any body, which, in a natural state, would so affect the body as to produce feeling.

"Another evidence that the soul acts through this fluid is afforded in the circumstance, that by strongly directing the attention to any part, as, for instance, the eye, a new sensation is perceived in the organ; and if this kind of attention be persisted in, or frequently repeated, the eye becomes inflamed and painful. It is also evident, that those nerves which belong to parts, the natural functions of which latter are carried on without our consciousness, such as the stomach, may be rendered sensitive by a strong action of the will; and the operation of all the reflex, or ordinary involuntary system, is modified by mental emotion. In fact, every thought changes the nerve current. Moreover, the brain itself, and all the nerves connected with it, are so far influenced by the will of the individual, as to be not only directed into new modes, so as to effect an entire alteration in the habit of mental and muscular action, but also to such a degree, that the completely organized brain is partly a creation of self-directing and self-repeating mental activity. It is, so to say, developed by the habits of the soul. How necessary, then, is early training! as we bend the twig so is the tree inclined--a trite axiom, but, nevertheless, very true.

"The rapidity of the mental processes seems to require an electric, or some similar medium, by which they may be effected in connexion with the body, since they result so instantaneously, that the will to move, for instance, and the motion, are simultaneous. Professor Wheatstone has proved, that electricity, like light, travels at the rate of 192,000 miles in a second, and this appears to be an agency sufficiently subtle to answer all the purposes of the soul as an active being. Probably electricity and light are but one agent, acting under different relations. It is interesting to consider ourselves, by each act of our will, as operating upon embodied light; but whatever be the immediate agency between mind and muscle, it is vastly more interesting to know, that willing being is something as really and distinctly existing as the light itself, but in its nature infinitely more subtilely and exquisitely constituted, since it is indivisably and inscrutinably associated with the Being who said, Let light be, and light was!"

"If we advance further in contemplating our mental existence with the body, we shall more clearly perceive that the body itself is not the cause, but the instrument of mind. In order that it should be a ready instrument, it is, as we see, constructed on electro-magnetic principles, so that it serves the purposes of the mind in many spontaneous actions, without even awakening consciousness. Whatever is essential to the processes of life is carried on in the economy without our consent; and until some demand is made by the body, requiring our voluntary interference for the removal of inconvenience, or the supply of aliment, our attention is not so far attracted to the body as that our desires are distinctly perceived to arise from its state. Thus, we feel hunger or thirst, and use means for their removal. But our emotions and affections are at all times influenced by bodily condition, and in many respects may be traced to a physical origin. They are so far involuntary, that their causes are in operation before we are aware, and they are apt to evince their power against our wills; yet reason is tested by their presence, and she prevails over them, in proportion to the clear perception and experience of spiritual motives, or those moral convictions which arise from religious enlightenment. Were it not that our connexion with the body subjects us to feelings against which we are conscientiously and reasonably required to contend, we should be incapable of that self consciousness by which we distinguish ourselves from our bodies. In fact, those who find no other inducement to thought and action than the body affords, are really incapable of apprehending any other than bodily existence, and they live not according to spiritual but sensual motive."

Dr. George Moore.

Granting the truth, or the approximation to truth, of the foregoing theory, it is evident, not only that whatever alters the force of the electro-galvanic currents of which the nerves are conductors, alters the condition of the mind in relation to the body, thus making impressions weaker or stronger; but that whatever deranges the tone or "timbre" of the nerves themselves, produces mental illusions which are sometimes of a temporary, sometimes of a permanent character. For example, in derangements of the digestive organs, partial loss of sight in one or both eyes, the appearance of black motes, specks, or flies floating in the atmosphere--coloured wavy lines or zigzags--nay, even strange faces, sometimes grotesque, sometimes terrific, palpable to vision like the air-drawn dagger of Macbeth, are by no means unfrequent phenomena.

But, besides these transitory effects of nervous derangement, there are others dependent upon a permanent condition of the nerves, which is not well understood. For example, some persons are incapable of distinguishing between certain colours, while at the same time there is no defect in the construction of the eye, as an optical instrument. Sir J. Herschell examined the eyes of a person affected with this peculiarity, and satisfied himself that all the prismatic rays had the power of affecting them with the sensation of light, and of producing distinct vision. Hence, therefore, as he observes, "the defect arises from no insensibility of the retina to rays of any particular refrangibility, nor to any colouring matter in the humours of the eye preventing certain rays from reaching the retina, as has been ingeniously supposed, but from a defect in the sensorium, by which it is rendered incapable of appreciating exactly those differences between rays on which their colour depends."

The degree of defect in these singular cases is variable, nor are the colours which the sensorium cannot appreciate by any means always the same. Generally, however, red and green are the colours which are not discerned, while blue and yellow seldom fail to make a due impression. Seebeck, on somewhat vague grounds, as we think, divides persons labouring under this defect of vision into two classes. The first consists of individuals who have a very imperfect power of distinguishing the impressions of colours generally; in these, at the same time, the defect is greatest with regard to red and green, these colours being not distinguishable from grey; blue is imperfectly distinguished, and yellow the most perfectly.

The second class consists of individuals who err with regard to the distinction of red from blue; and who, as in the first class, recognise yellow the best. It is not, as we have said, to the eye itself that we are to look for the cause of this defect, but to some mysterious peculiarity of the sensorium, or to some want of harmony between the brain and the optic nerves; but whether the failure is in the energia of the optic nerves, or in the sensorial power of the brain, we pretend not to say. We have, in fact, in this instance, as in so many others, only to confess our ignorance. It is scarcely needful for us to add, that this visual defect is irremediable.

But there are defects of vision dependent upon the structure of the eye itself, as an optical instrument; and under this head we may first notice myopia, or near-sightedness. Myopia results from an over-refractive condition of the eye, the rays of light passing from any object being brought to a focus in the vitreous chamber of that organ, before reaching or impinging on the retina. In this case, either the cornea or the crystalline lens is too convex, or both are in this condition, or the humours of the eye generally are too dense or too abundant, and the pupil is large. Persons thus affected see all objects indistinctly which are viewed at the ordinary distance of distinct vision, but objects held close to the eye are seen with microscopic accuracy. The distance from the eye, when in a normal state, at which objects are surveyed with the utmost distinctness, is from fifteen to twenty inches. An eye which cannot discern objects with ease and accuracy beyond ten inches, may be considered as myopic; but not unfrequently persons affected with myopia cannot regard an object with distinctness which is beyond four, three, two, or even one inch distant from the eye.

To myopic persons, objects brought within their sphere of vision appear magnified; a small type is read more easily than a large type; and, indeed, such eyes see better through a pin-hole in a card than when not thus assisted; the reason is, that the pupil, from its dilatation, admits too many rays of light, but by diminishing the aperture through which the rays of light are admitted, all but those which are the most direct are excluded, and the images on the retina will be, therefore, the more defined. On the same principle, myopic persons, when endeavouring to see distant objects, half close the eyelids, (hence the term myopia, from μύω, I shut, and ὤψ, an eye.) Myopic persons generally see better in the dusk, or at twilight, than others; and their sight, though short, is strong and good, often lasting. It has been asserted, that as the eye flattens in age, the vision of myopic persons will improve as they advance in life, and the theory, it must be acknowledged, seems feasible, but experience proves that this is not the case; indeed, it would appear that the myopia rather increases than diminishes.

Concave glasses greatly assist the myopic eye; they cause a divergence of the rays of light before entering the pupil, and thus counteract the over-refractive condition of that organ. The degree of concavity best suited to particular cases can only be determined by trials.

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.

We have already intimated, that the obliteration of one organ of sense tends to the greater perceptibility or acuteness of others. This follows almost of necessity, because the loss of any given organ tends to the more finished education of those which are destined to aid it. Thus, in a blind man, the hearing is generally more than usually acute and accurate, as is also the sense of touch; while, at the same time, the muscular sense is surprisingly elevated. Blind guides have been known and celebrated for their extraordinary gifts in the wildest moorland and hilly districts. John Metcalf, of Knaresborough, (1717,) was road surveyor and contractor in the Peak of Derbyshire; he built bridges over rivers, and projected roads over the ridges of the Pennine chain, nor was he less remarkable for feats of daring, such as hard riding, swimming, etc. This person was blind from infancy. How wonderful is the elasticity of the human mind, which can reconcile itself in such an astonishing manner to the most adverse circumstances, and triumph, as it were, over the loss of that inestimable possession--sight! Many men of note, who were either born blind, or had lost their sight at an early period, have figured in the scientific, literary, and musical worlds. A few of these may be here mentioned (without going back to long past centuries, that is, to the days of Homer, or Diodatus, or even to the more recent time of Henry, the minstrel of Scotland, born blind 1361, or of sir John Gower, of London, who died in 1402.)

Take, by way of example, the following:--Huber, the naturalist (Geneva, 1784-85); he became blind at the age of seventeen; he wrote on the labours and instincts of bees and ants, and also on education. Francis Potter (London, died 1678); he wrote on mechanics, theology, and painting. F. Carulhi (Nantes, died 1789); born blind; he wrote on music. Rev. J. Troughton (Coventry, died 1681); blind at four years of age; he wrote on theological subjects. John Stanley (London, died 1781); blind at two years old; a musical performer and composer; he wrote the oratorios, Jephthah, Zimri, etc. John Gough (Kendal, 1757); blind at the age of three years; a writer of several communications to the Manchester Society, and to Nicholson's "Journal on Botany and Natural Philosophy." Sir John Fielding (Westminster, died 1780); blind from youth; police magistrate, and author of the "Universal Mentor." John McBeath (Dalkeith, died 1834); blind at an early age; he studied music and mathematics, and wrote on "Inventions for the Blind." He was a blind teacher in the Edinburgh school. James Wilson, author of the "Biography of the Blind." James Holman, whose published travels through many portions of the world have excited very general curiosity and interest. Alexander Rodenback, member of the Belgian Chamber of Deputies, and one of the principal actors in the Belgian revolution; he was a supporter of the democratic party, and often made the chamber ring with his original and eloquent speeches.

We might add greatly to this list, but we select the above merely as examples, to show how, when the acquisition of knowledge is debarred at the entrance of the eye, the mind will collect it through the inlet of other senses. Of the numerous schools of instruction for the blind, of which our country may well be proud--of the systems of training pursued in them--of the labours of pious individuals, some themselves blind--it is not our place here to speak. We devoutly pray that the blessing of the all-seeing God may be with them and upon them!

Blindness is sometimes, but, we are happy to say, not very often, accompanied by deafness--utter deafness. Blindness is a sad calamity; but when blindness and deafness meet in the same object, what a deplorable picture presents itself to every feeling heart! Blind, deaf, mute! Christian reader, reflect--by what means, by what process, shall access be gained to the undying mind? How can we, by human means, instil into the soul the glad tidings of salvation, demonstrate the corruptness of human nature, the necessity of a new birth, the efficacy of prayer, and the perfections of the triune Jehovah? Think of an immortal soul imprisoned in such a rayless, silent tenement, debarred from all acquaintance with the world around, except as far as feeling may go, and taste and smell. But God often works in a mysterious way, and perhaps communicates light to the mind, when the visual orbs are sealed up in darkness, and the invitations of Christ cannot be heard from the lips of his pious minister--the good shepherd, who is commanded to care for the little ones of the fold. Oh! how thankful to our gracious God ought we to be, for the full use of all our senses--those inlets to the knowledge either of good or of evil, nay, of both; but let us say, "I and my house will serve the Lord!"

The following account is condensed from the "American Annals of Education," and from captain Basil Hall's "Travels in North America." It refers to the deeply touching and most interesting case of Julia Brace, a deaf, dumb, and blind American girl, who resides in the Institution for the Deaf and Dumb at Hertford, Connecticut: "Julia Brace was seized with typhus fever at four years of age; during the first week of her illness she became blind and deaf; she retained her speech for about a year, (the tongue acting mechanically, according to acquired muscular habit,) frequently repeating her letters, and spelling the names of her acquaintance; but she gradually lost it, and seems now condemned to perpetual silence. For three years she continued to utter a few words; one of the last was 'mother' (that word clung to her tongue; it was the earliest she heard and spoke, and the last that died on her lips!) At first she was unconscious of her misfortune, and imagined that a long night had come upon the world. At length, in passing a window, she felt the sun shining warm upon her hand, and she made signs indicating she was aware of it; she was governed by her mother, by means similar to those employed in the case of Mitchell. At first she was exceedingly irritable, but she became at length habitually mild, obedient, and affectionate. At nine years of age she was taught to sew, (wonderful the conjunct operation of the nerves of sensibility and muscular sense!) and since that time to knit. Julia Brace, who is now nearly thirty years of age, is supported in the Hertford Asylum, in part by the contributions of visitors, and in part by her own labours in sewing and knitting. A language of palpable signs was early established as a means of communication with her friends; this has been much improved by her intercourse with the deaf and dumb, and is now sufficient for all ordinary purposes. It is obvious, that her means of perceiving external objects are the smell, the taste, and the touch. The touch is her chief reliance, and enables her to distinguish every object with which she has been familiar, sometimes by the aid of her lips and tongue; but her smell also is surprisingly acute, and often enables her to ascertain facts which are beyond the reach of other persons. Her countenance as she sits at work exhibits the strongest evidence of an active mind and a feeling heart, and thoughts and feelings seem to flit across it like the clouds in a summer sky. A shade of pensiveness will be followed by a cloud of anxiety or gloom; a peaceful look will perhaps succeed; and not unfrequently a smile lights up her countenance, which seems to make one forget her misfortunes. But no one yet has penetrated the darkness of her prison house, or found an avenue for moral or intellectual light." Blindness alone is a great calamity. Milton most affectingly deplores his deprivation:--

------------"Not to me returns Day, or the sweet approach of ev'n or morn; Or sight of vernal bloom or summer's rose; Or flocks, or herds, or human face divine,-- But clouds instead, and ever during dark Surround me, from the cheerful ways of men Cut off; and for the book of knowledge fair Presented with a universal blank."

There are two morbid conditions of the eye of which we ought not here to omit, at least, a passing notice; we allude to hemeralopia, (ἡμέρα, the day, ἄλαος, blind, and ὤψ, the eye;) or, in other words, day-blindness; and to nyctalopia, (νὺξ, the night, and ὤψ, the eye,) that is to say, night-blindness. We may observe that many modern writers, as Scarpa, and others, have reversed the plain meaning of these terms, and have considered hemeralopia as denoting sight during the day, and blindness during the night; and nyctalopia as expressing the power of vision by night, but not during the hours of daylight. In order to prevent any confusion or misunderstanding, we shall drop the scientific terms, which by some are so strangely misconstrued, and adopt their English equivalents. Perfect day-blindness, or owl-sight, as the French call it, is of rare occurrence. Dr. Hillary never met but with two examples; at the same time he notices a report, that there are a people in the East Indies, and also in Siam, who are subject to the disease of being blind in the day-time, yet who see clearly by night.

Mod. Univ. Hist. vol. vii.

Day-blindness most probably never occurs as a separate disease; it is immediately the result of a peculiarly irritable state of the retina, insomuch that the stimulus of daylight cannot be borne; and not of the retina only, but of the iris also, which, in order to exclude the rays of light, closes the pupil of the eye to a mere point. All have heard of those singular beings termed Albinos.

Albinos are found among all nations, and are noted, from contrast of colour, in African and not unfrequent among the dark tribes of Africa; indeed, it would seem that there are families of negroes in which there is an hereditary tendency to the production of Albino children.

See Dr. Prichard's "Researches into the Physical History of Mankind," vol. i. p. 366.

Among the lower animals, albinism appears to occur most frequently in the race of tame rabbits; they are known by their white fur and red eyes; breeds of these may be propagated; the same observation applies to white mice.

Human albinos, at least, and probably albinos in the animal grade, are affected by a certain degree, more or less decided, of day-blindness. The characters of the albino result from a deficiency in the colouring principle, common to the skin, hair, and eyes. The eyes, for example, are entirely destitute of the dark pigment; in fact, the pink, or red colour, so observable, depends on the fine vessels which are very numerous in the composition of the iris, and on the still greater number of minute arterial ramifications which almost entirely form the choroid membrane, and which, under this condition, are seen through the pupil. To Albinos the state of the eyes is their greatest source of inconvenience. The absence of the black pigment, which has the important office of absorbing superfluous portions of light, renders the eye preternaturally sensible of this stimulus. Strong lights affect the organ painfully; even the glare of open day produces a partial blindness, and the admission of light is intolerable. These evils are balanced in some measure by superior power of vision in dusk, or imperfect darkness.

On this subject see Buffon, Supplement, tom. iv. p. 559; Pallas in his "Novæ Species Quadrupedum," pp. 10, 11, n., and also Blumenbach, etc.

Let us now turn to night-blindness. "Nocturnal blindness," says Scarpa, "is properly nothing but a kind of imperfect periodical amaurosis, most commonly sympathetic with the stomach. Its paroxysms come on towards the evening, and disappear in the morning. The disease is endemic in some countries, and epidemic, at certain seasons of the year, in others. At sunset, objects appear to persons affected with the complaint, as if covered with an ash-coloured veil, which gradually changes into a dense cloud, intervening between the eyes and surrounding objects. Persons thus affected have the pupil, both in the day and night-time, more dilated and less movable than it usually is in healthy eyes. The majority of them, however, have the pupil more or less movable in the day-time, and always expanded and motionless at night. When brought into a room faintly lighted by a candle, where all the bystanders can see tolerably well, they cannot discern objects at all, or at most in a very feeble manner, or they only find themselves able to distinguish light from darkness, and by moonlight their sight is still worse. At daybreak they recover their sight, which continues perfect all the rest of the day till sunset."

Cap. xix. p. 322. Ed. 8vo.

Mr. Bamfield observes that the abolition of eyesight by night has occurred in all ages, and is a common disease of seamen in the East and West Indies, the Mediterranean, and in all hot and tropical countries and latitudes, and that it affects more or less the natives likewise of those regions of the globe. It also occurs frequently among soldiers in the East and West Indies, but, according to the information he has received, it is by no means prevalent amongst sailors employed on shipboard. It is not an uncommon complaint among the Lascars employed in the East India Company's ships, trading between India and Europe. Celsus has remarked that females in due health are exempt from this strange affection of the orbs of vision. It may further be observed, that the inhabitants of northerly latitudes are less subject to night-blindness than are the natives of tropical countries in theirs; but that when the natives of cold climates visit the tropics, they are peculiarly susceptible to this morbid condition of the eye.

Lib. vi. cap. vi.

But we must now pass from the eye to the ear. Deafness from infancy, that is, total deafness, involves the loss of speech, or of the utterance of a definite language. The deaf do, indeed, utter wild cries, and, as if impelled by instinct, scream with rage, howl with pain or fear, and mutter when pleased; but they hear not the sounds which they themselves utter, and which are often harsh, and even terrible.

The grand object for which the sense of hearing was given to man was for understanding, acquiring, and using language, or speech, for the enunciation of which the lips, the teeth, the tongue, the palate, in fact, the whole organization of the mouth and lower part of the face, is expressly modified, as is also the conformation of the larynx; but, be it observed, that without mind man could never have been a speaking animal. Here, then, we see a design often overlooked by those who study the economy of man. The ox hears, but it could not talk or utter language--that is, sounds modified in accent, in termination, in length--even if it would, for the organization of the vocal organs would prevent the required intonations; but as the lower animals are not destined to think, to argue, to admonish, to persuade--in short, as they are not destined for immortality--in them the faculty of speech would be out of harmony with their real condition and destiny. Language is a mental as well as corporeal exercise, for we have to learn what each sound uttered means, till at length it becomes natural to us, if we may use a popular expression. We have already alluded to the pleasure which the mind derives from music. Now, there are a few observations regarding deafness, or the deprivation of hearing, which cannot be out of place. Total deafness from various causes may take place in a person of mature years, or after he has advanced in life to years of adolescence; in such cases language will be retained, but the voice will be under no control, no modulation--one sentence may be shouted, another spoken in a whisper.

We may adduce a case in point: an officer (a nobleman) in the battle of Waterloo had his auditory nerve destroyed by the concussion of the air from the bursting of a shell, or from the report of a cannon. He became totally deaf, and consequently lost all control over his voice, which became discordant, and difficult to be understood even by those who were his intimate associates. A similar instance is mentioned by an American writer, in which entire deafness, taking place at the age of eighteen, so affected the articulation, that the individual was no longer intelligible, even to his nearest friends. But, besides total loss of hearing, whether congenital, (that is, from birth,) or occurring at any future period, auditory incapacity manifests itself in various degrees, and under singular modifications. For example, a friend of the writer, who is extremely musical, and plays brilliantly on the piano, is so deaf that she scarcely understands a word of the conversation of persons around her; yet let a discordant note be struck, and she feelingly appreciates it. Another lady, with whom the writer is acquainted, cannot hear the shrill high-toned squeak of the shrew-mouse; and the writer knows some who cannot hear the cries of other shrill-toned animals, as the bat, or mouse, while to deeper, not louder notes, their ears are perfectly awake.

"Dr. Wollaston constructed a small organ, whose notes began where the notes of ordinary instruments end; the notes of his organ increased in sharpness till they became inaudible, though he was certain that it continued to give sound, from feeling the vibrations equally with the lower notes. He thus found that some people could hear seven or eight notes higher than others, and that children could generally hear two or three notes higher than grown-up people. In some persons, the accuracy of the ear is merely impaired in distinguishing faint sounds, and sounds somewhat similar; instances of this kind are particularly evident in infants, whose first attempts at speech are a very remote similarity to the sounds they hear, and become more perfect as their ear is educated, and in some cases remain imperfect through life, in consequence of defect in the organs of hearing. All imperfections of speech do not arise from imperfect hearing; an indistinct articulation may result from various other causes; from carelessness, from defective organs of speech, or from an imperfect formation of those organs; from irregular respiration, producing hesitation, and in some instances proceeding from nervousness."

See Dr. Arnott's "Elements of Physics," 1827.

The writer is acquainted with a lady, whose organs of hearing are in full activity, but she cannot distinguish one tune from another; her ear appreciates piano, forte, or fortissime, but neither modulation nor rhythm. The defect here must be in the mind, (a phrenologist would say that the organ of music in the brain was undeveloped,) yet this lady is sensible, pious, and strenuous in her exertions for the extension of the knowledge of Christ.

To revert, however, to the deaf and dumb (or deaf-mute) not deprived of eyesight, we may observe, that these persons, formerly neglected and deemed incapable of instruction, are not now excluded from the school of knowledge and of religion. Men have at length confessed that they possess rational souls--that they are capable of receiving information--and that the mind may be made the recipient of a certain amount of knowledge, varying of course according to the natural powers of the intellect. Not that the amount of knowledge acquired by such persons can ever, cæteris paribus, equal that which may be acquired by those who labour under no defect; nevertheless, the inferiority is only one of degree, and is easily accounted for. An able writer makes the following pertinent remarks: "From the advantages which instruction has afforded to a certain proportion of the deaf and dumb for the last half century, a tolerably correct estimate may be formed of their capabilities for improvement. The deaf-mute, living in society, but without instruction, must be regarded as one of the most solitary and melancholy of beings. He is shut out from all but the most imperfect intercourse with his species, and the very intellect, by the possession of which he is raised above the lower creation, serves only to heighten his calamity, and render the sense of his deprivation more acute. His perceptions of external objects are indeed accurate, but superficial, and confined to a very small sphere.

"Of the various arts by which the necessaries and conveniences of life are produced, he can have no knowledge beyond that which is included in the range of his own vision. Animal desires he feels, and he is led by the conventional usages of society to the performance of moral duties, and the avoidance of open and flagrant crime. Thus he becomes experienced, as other human beings are, in what is right or wrong. He sees that virtuous actions have a certain amount of reward in the opinions of good men, for he learns to discriminate between those whose actions are proper, and those who do wrong; and, again, he sees that in many cases vice meets with disapprobation and punishment among mankind. How this kind of experience shall affect his own conduct, must depend not only on the circumstances in which he is placed, as to example, and the moral influence of those with whom he has to associate, but also on his own natural tendencies. The performance of moral duties implies the exercise of intellectual faculties, and from his birth the deaf-mute makes use of his reasoning powers. He is subject to changes of purpose, to changes of feeling, the pleasures and the infirmities common to his species. He is sensible of kindness; he gives proof of affection. That such is the uneducated state of the deaf and dumb might be proved by the observations of their parents, friends, and instructors, in hundreds of instances. That such must necessarily be the case, supposing them not to be idiots, it would be easy to show. We affirm, in contradiction to those who contend that deaf-mutes are naturally more debased than other men in intellect and in morals, that there is not an individual deaf-mute, now under instruction, improving, and thereby evincing rational faculties, who, previous to his instruction, however disadvantageous the circumstances which attended his earlier years, did not evince moral sentiments and intellectual operations. We have traced the history of many of this class, in different ranks of society, down to the period when the deprivation under which they have laboured was first ascertained; and we have invariably found that mixture of good and evil in their actions and tendencies, which is seen amongst other children. We have also had sufficient proofs of the exercise of intellect even while they were in a state of childhood. The parents of deaf and dumb children can sufficiently attest the truth of these observations."

The writer can attest them: he can adduce facts within his own knowledge, proving the correctness of the views entertained by the author just quoted; reasons, however, sufficiently obvious prevent him expatiating on this part of the subject, and, indeed, have influenced him in adopting the words of another, whose means of observation have been very extensive. We cannot here enter into the modes of instruction employed in order to illuminate the minds of the deaf-mutes; all we need say is, that it is by a system of apt signs, or of hieroglyphics, at least in the commencement; but minds of capacity soon advance still further; reading and writing are acquired--nay, even the power of articulate speech. But we must pass from this part of our subject, on which indeed much might be said.

The senses of smell and taste require a passing notice. We conjoin these senses together, because the latter depends much for its discrimination on the functional perfection of the former; in fact, much of that which in the enjoyment of food is commonly attributed to the sense of taste, depends on the odour carried from the mouth to the nose. If, for example, we masticate any spice, or aromatic substance, as cinnamon, while at the same time the nostrils are strongly compressed, and breathing through those channels obstructed, we perceive no definite flavour from the spice, although the essential oil expressed may sting the tongue and palate. Stoppage of the nasal passages, from catarrh, influenza, or other affections, and preternatural dryness or thickening of the schneiderian membrane, impair or destroy both the sense of smell and taste. We may here observe, that irritation of the schneiderian membrane by ammonia, by snuff, and other things of the like nature, has nothing to do with the sense of smell residing in the nerves of that membrane: smell is the appreciation of odours; any delicate membrane may be irritated, as, for example, the conjunctiva of the eye. With irritants, scents may be combined; in such admixtures for the stimulation of the olfactory nerves many persons eagerly indulge, and under certain circumstances they are medicinally useful; but it is the perception of scent or odour, irrespective of irritation, which is the proper function of the olfactory nerves.

With respect to taste, this sense resides in a branch of the fifth cerebral nerve, called, from its function, gustatory. For the sensation of taste, moisture must be present; an utterly insoluble body, as crystal, is tasteless; we reduce to a pulp, by means of the teeth and the saliva, the food which we eat, excepting, indeed, such articles as come under the denomination of drink, or, in other words, viands in a fluid state, such as wine, ale, coffee, etc. Perfectly pure water is tasteless.

The contact of two metals in the mouth, producing a galvanic discharge, excites a sensation or flavour which cannot be well described; but the moisture of the saliva is requisite for the effect. It is said, that the superior flavour of porter drunk out of a pewter vessel results from a slight galvanic action going on. Mr. Mayo says, "various substances, after exciting the sense of touch on the fauces, and that of taste on the tongue, are capable of producing a third impression, which is popularly referred to the palate, but which is really felt upon the sentient membrane of the nostrils." In the case of metals taken into the mouth, this mode of the reception of flavour would appear to take place.

Loss of taste, like that of smell, may arise from various causes; when the mouth is parched up by fever or intense thirst, the sense of taste is greatly impaired, or even altogether suspended; but this condition may be regarded as temporary. A few instances have come under our own observation, in which, though the senses of smell and taste were not obliterated, they were extremely obtuse, insomuch that the most nauseous medicines or offensive odours created no feeling of repugnance or disgust, and the most delicate viands, or the fragrance of sweetest flowers, no pleasurable sensation. In idiots, this loss of taste and smell is far from being uncommon; but it is not to such that we here allude, nor is it to those who have suffered from repeated partial strokes of paralysis or apoplexy, but to persons of sane mind and sound health. In such cases, the deficiency is either in the sensitive and conducting power of the nerves, or in some a loss of tone in the portion of the brain to which they immediately lead--at all events, a barrier is interposed between organic structure and the mind.

As far as the operations of intellect are concerned, the loss of smell or of taste is of secondary consideration; these senses administer to our animal enjoyments rather than to the spiritual part of our being; nevertheless, mind and body are so united that the breath of early flowers, the incense of the fields, the balmy breeze, the taste of wholesome food, or of the refreshing draught, call forth the feelings of the mind, awaken gratitude, and lead us to offer up our thanks to Him who is the Giver of every good.

With respect to the sense of touch, we have few additional observations to make; this sense is trained to its highest perfection in those who are born blind, and who from early childhood have acquired the habit of supplying by its exercise their visual deficiency, as far as one sense can compensate for the loss of another. In the educated blind, the faculty of distinguishing minute differences in impression, and of receiving from a given surface of sentient integument the largest number of separate sensations of contact, appears most remarkably developed; in the blind, too, the exploring movements of touch are performed with the most skill and delicacy. To so high a pitch, indeed, is the sense of touch elevated, that many have been led to believe that the blind are even capable of appreciating colour; it may be, we admit, that they are able to detect by touch certain differences of texture, which depend on the chemical processes of dyeing, or on certain modes of preparation connected with the impartation of colour to the surface of objects, and thus discriminating or analyzing, may be taught to associate the name of blue with one sensation, of red with another, and so on--more than this is impossible.

Obtuseness of feeling, or of tact, arises from various causes; the horny hand of the labourer is less discriminative than that of the man who is not called to toil in the field, or work at the anvil. As regards feeling, independent of the pure sense of touch, there is much difference even among individuals, according to the general nervous susceptibility of the frame. Among the North American Indians this susceptibility is less than among Europeans, as may be concluded from the horrid details given by Mr. Catlin, and others, who have witnessed the revolting practices of the red men of the western world.

Loss of feeling, or of tact, in one or more limbs, is the result of paralysis, and other morbid conditions of the system, to which our frail tenement is subject. The same observations apply to the muscular sense, which sense is moreover deranged, or suspended, during a fit of intoxication, (Proh pudor!) or when placed on some dizzy height, one, unaccustomed to such a situation, is agitated by extreme terror. The sailor in the rigging of the topmast, the cragsman of the Hebrides, the hunter of the chamois, have learned to surmount such a sense of fear, and are secure in their place of peril. The loss of sensibility, and the loss of the muscular sense, can never pervade the whole frame, till that hour arrives when the soul is about to quit its mortal abode, and enter the regions of another world. To this condition all are destined--the sentence of death is gone forth! Oh that, while living, while in the enjoyment of our senses, and of the energies of our body, we may "lay hold upon eternal life," and live as "dying daily!" Let us aim at being able to appropriate to ourselves the expression of the psalmist, "My flesh and my heart faileth: but God is the strength of my heart, and my portion for ever." No one can say this in verity, who is not established on the "Rock of Ages."

Psa. lxxiii. 26.

The Almighty has not designed that man, even in this his probationary state, should pass through his pilgrimage without experiencing pure pleasures and delights. It is to these that the senses administer, each in its appointed way. The sublimity and the beauty of natural scenery--the grandeur of mountains, forests, and seas--the glory of the sun, moon, and starry expanse above--the works of art, towers, and temples--all these, and more, received into the mind through vision, produce the most delightful emotions. The flowers that strew our pathway, the insects glittering in the sun, the waving cornfields, the grazing cattle, the rustic cottage of the hardy labourer--all combine to fill the soul with pleasure and thankfulness. Can we listen to the roar of waters, to the deep murmur of the wind rushing through the forest, to the song of birds, or the notes of sweet melody, and feel no pleasure--no spirit of praise and gratitude? Is not food sweet to the healthy appetite? Do we not rejoice in our strength, in the use of our limbs, and in our manual address and precision? Are not the perfumes of flowers, the scent of the bean-field, of the bower of honey-suckle, of the new-mown hay, delicious? Is not the earth full of riches? Has not the Creator adapted it to our pleasures, as well as our necessities, and endowed us with every sense requisite for enjoyment? How delightful to the Christian--how doubly enjoyed by him is nature in all her phases, in all her manifestations, in all her variety! To him nothing is uninteresting, from the mightiest creature to the animalcule, from the cedar to the humble weed; and reflecting that knowledge stores his mind, and pleasure gladdens, refreshes, and animates him, through each respective medium; and delighting in life, and life's enjoyments, he praises God for every bodily and mental endowment, and for all the glorious works which his hands have created--works which lead him to muse upon that inscrutable wisdom, power, love, and consideration, which the Almighty has displayed in fitting the earth for him as his temporary abode--glorious in its mountains, its plains, its seas, and rivers--glorious in the light of day and the darkness of night--glorious in the air and the clouds, in the lightning and the rainbow; but yet an abode to be exchanged by the believer for one infinitely more glorious, in which sin and pain are unknown, and from which mortality is banished for ever.

Transcriber's Notes:

Page 65: Contrary to the other sections, section 8. of CHAPTER I. has no header in the original.

Footnotes have been moved to directly under the text they refer to.

Changes made to the text:

Page 19 (table): "Heats" in the right column changed to "Heat"

Page 67/68: Added a "." at the end of the footnote

Page 153: The original read "CHAPTER V." as heading of the last chapter, this has been changed to "CHAPTER IV." as there are only four chapters.

Page 178: Quotes removed (originally: in others." At sunset,)

Page 179: "effects" changed to "affects" (it affects more or less)

Page 184: Quotes added ("Of the various arts)