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from too great a volume of blood circulating in the vessels ramifying over it, or from blood effused upon its surface, apoplexy, paralysis, and death, are the results.

In advancing to direct our inquiries respecting the impressions received through that power of the nerves termed percipient sensibility, we shall observe, in limine, that a distinction is to be drawn between the vividness of sensation, and the accuracy with which the mind judges of objects by sensation, or, as it is termed, accuracy of feeling.

The first time that any stimulus acts upon the senses, it in general produces a vivid sensation; but the liveliness and vividness of impressions become diminished in proportion as the action of such stimulus on the senses is repeated; and by these means, the sensation may be at length almost annihilated; which effect is produced in common language by habit.

Sensations can, in some degree, be rendered, at will, more vivid and intense; and the Author of our frame has also endowed us with the faculty of moderating and diminishing them. Thus, if we wish to render a sensation as impressive as possible, we dispose the organs of sensation in the most advantageous manner, we direct the whole nervous sensibility to one particular part,-we receive but a small number of impressions at the same time, applying all our attention to them :-hence, a great difference is established between merely seeing, and regarding attentively; between hearing, and listening. On the other hand, when we wish to moderate the vivacity of any sensation, we either generalize (if the term be allowed) the nervous sensibility, or direct it intently to another object ;-for instance, if I happen to be in a room where conversation is passing, to which I wish not to listen; if I direct, by a sort of mental force, my attention to some object, as the examination of a painting, or engage myself in thinking on a subject which requires a more than common exertion of the mind,

I shall not hear a word of what is spoken; and the same effect will be produced, if I abstract my attention totally from every thing around me, and fix my thoughts, as it were, on vacancy, assuming a state of mental abstraction, called reverie.

We have already previously observed, that it is through the medium of sensation we become aware of our own existence, and the existence of surrounding objects. The sensations by which we acquire this knowledge, various and complex as they may be, have been, by some writers, referred ultimately to two classes, viz. pleasure and pain; and although numberless sensations, which we perpetually experience, appear to excite in us neither the one nor the other, we must not too hastily conclude that this arrangement is without foundation; for let us reflect on the modification which habit produces-how soon even pain becomes less irksome, and pleasure a matter of indifference; and remember how those circumstances, which on their first occurrence produced feelings of delight, are now little noticed by their continuance or frequency; at the same time considering, also, how in childhood, when the system is as yet new to the crowd of sensations which are about to call forth the exercise of untried faculties, no occurrence is indifferent, but a cause either of pleasure or of pain, and we shall be more ready to yield our assent. Besides, too, it must be allowed, that although numberless sensations (and it is wisely so ordered by Providence) do not draw us from our duties by the pleasure or pain they communicate, a slight or unusual increase of any of such sensations immediately determines it decisively to the one state of feeling or the other.

It is by a wise and merciful arrangement, that without any process of reasoning, without the aid of reflection, we instinctively withdraw from whatever inflicts pain, and are so led to avoid at once whatever militates against the safety and preservation of our animal frame ;—and hence

arises a natural love of pleasure, which, were we like the brutes that perish, it would be well to indulge in; but which reason and religion teach us to enjoy with moderation, or forego altogether, when (as is too often the case) such indulgence would render us useless and unworthy members of society.

We have already intimated, that sensation supposes a common sensorium, to which every impression must be referred. Hence certain animals of the lowest rank, we may conclude with reason, feel nothing; or at least, nothing analogous to what we call pain or pleasure; and here again we see proofs of wisdom. These animals are all incapable of avoiding injuries, to which they are continually liable; hence, did they feel, their existence must of necessity be one of unavoidable suffering; but such is their organization, and their tenacity of life, that they are not only divided into parts with impunity to themselves, but in many animals the parts become distinct existences.

acquired; for it has been observed that a more than usual development of one is generally attended by a deterioration of the rest; and that when one is lost, some of the others are rendered more acute. Thus, in the blind, we often see an extreme liveliness and vigor of feeling, so that by the touch alone many are able to distinguish even the varieties of color: this faculty, of course, is gained only by habit and frequent practice; but were the organs of all the senses perfect, such a result would never arise, even from the most assiduous application.

The different senses, as they are termed, although possessed by all the animals of the higher class, that is, by mammalia and birds, are not disposed among them in the same degree; nor even among all the tribes of which the human race is composed; since it appears, that different nations are more or less gifted in various points, according to their necessities, habits, and modes of life. For instance, man, in civilized society, endowed with vision sufficiently clear and distinct, possesses not this faculty in so powerful and extensive a degree as the Arab or American Indian; but over the most gifted in this respect of the human race, many animals, especially of the feathered tribe, have amazing advantage. The eagle, towering above the clouds beyond our sight, or seen only as a dark speck in the sky, surveys the wide extent of the mountain-range or plain below, and marks his prey at an almost incredible distance. The sense of smell in the dog, the vulture, and many other animals, is extremely acute and discerning; for it is by the exercise of this faculty, principally, that they are enabled to procure their

With respect to accuracy of feeling, (and in this expression we would include all the senses,) we have to remark, that it is acquired only by practice and experience; and hence, the eye is enabled to judge correctly of size and distance, as well as of the minute gradations of color. For example to an infant, or to one born blind, but whose sight has been lately restored, distant objects seem as near as those that are so; for a knowledge of perspective, of relative size and proportion, is yet to be gained ;-by degrees, however, the eye begins to discriminate with accuracy, and at length the sense is perfect. It is thus, also, with regard to the ear: it is, for the most part, practice alone, food. But to man, having no need of which enables us to distinguish, by the medium of this organ, between discord and harmony, and every modulation of sound; and by practice, the sense of taste likewise becomes refined and discriminating. An equally complete perfection of all the senses at once, seems almost impossible to be

this, and in every climate depending on means far different for his support, Nature, bountiful, but not lavish, has denied a gift, which, if possessed in so great a degree, would be of no utility, if not an actual disadvantage.

In the sense of hearing, as it respects distance, although man is infe

rior to many animals, none possess an ear so highly discriminating and susceptible; nor does it appear that in other animals this delicacy (as far as they do possess it) can be corrected and improved; among mankind, however,

we must allow considerable difference to exist. Some individuals, for instance, are susceptible, from birth, of a peculiarly pleasurable emotion from certain successions of modulated sounds, termed music; and the individuals thus deriving pleasure, are said to have a musical ear. To others, on the contrary, music affords no pleasure; and some can scarcely distinguish one tune from another. Still, however, a taste for music may be acquired, provided the ear be capable of discriminating well between each variety and modulation of tone, or, in other words, be, as it is commonly termed, nice. I think we must allow, that a nice and a musical ear are distinct from each other; for (though it commonly may be so) it does not follow that an ear, possessing great discrimination between sounds, should derive much pleasure from them; yet still, by such an ear, a musical taste may certainly be acquired.

With regard to other animals, although some are delighted by melody, or a succession of simple sounds, yet it does not appear that they derive that peculiar gratification from harmony which man so universally enjoys, or at least may, by cultivation.

The sense of taste, we may reasonably conclude, man possesses in a degree decidedly superior to that of all inferior animals; for although he is certainly unable by this faculty to distinguish poisonous or noxious substances, from those of a contrary nature, which we see exemplified in many animals, especially of the herbivorous class, by their rejecting those plants whose effects are known to be injurious to them; yet as this faculty is evidently the result of an instinctive perception, and therefore unconnected with delicacy of taste, it will hardly be allowed probable, that, as it is unnecessary, they should possess it in a

higher, or in so high a degree of perfection as man, in whom we know this sense to be capable of such modification and refinement. The class of birds and fishes are in this point, beyond dispute, considerably below man and the mammalia; and yet these are also able to discriminate in the choice of their food, being guided merely by instinct. Hence, as it appears that it is by instinct that the lower animals are guided in the selection of food, refusing or accepting, according as it dictates, and not liking or disliking from a refined delicacy of taste, there is no reason why this endowment, in a degree equal to what man enjoys, should be assigned to them, as some physiologists have done.

In the sense of feeling, a property diffused so universally throughout all animated nature, man stands supremely preeminent. To every part of his frame this power belongs, but the hand alone can distinguish and appreciate; it is the regulator of the sight, and corrects its errors and mistakes,—it informs us of the size, figure, consistence, dryness, or humidity, and to a certain degree of the temperature, of bodies; and is, besides, capable of a degree of perfection scarcely credible. But among the brute creation delicacy of touch is not necessary; nor is it indeed compatible with their mode of existence. Yet if we survey the animal world, we shall find that each, according to the intellectual powers (we crave a license for the expression) of the class or order to which it belongs, possesses this sense, refined to a greater or less extent; for it would seem, that between the powers of judgment and reflection, and delicacy of touch, there exists a considerable connexion; as if the latter was given to inform, aid, and direct these mental operations, and bring more accurate information upon objects, of which juster ideas will thus be gained, and on which the mind may thus be more advantageously exercised. But as none approach mankind in mental powers, so none in this respect also

are equally endowed. Indeed, if we except the ape tribe, whose anatomical configuration approaches closely to that of man, we do not find any orders of beings endowed with, and using the hand, like man, as the grand organ of touch, and capable of such exquisite improvement.

But among the assembly of lower animals, the elephant stands conspicuous, unique, and remarkable for the peculiar organ of touch with which nature has invested him. He has not a hand, but his proboscis, with what may well be called a finger at its extremity, and which is sensitive and pliable, gives him a vast and decided advantage. He is thus enabled, not only to gather his food, which he does by means of this instrument, and convey it to his mouth, but to pick up and examine substances extremely minute.

But as it respects the brute creation in general, although many animals, as the squirrel, the cat, and others, make a considerable use of the arm, if it may be so called, and are certainly furnished by its means with the sense of touch to a limited degree, still we do not find this member terminating in a hand-flexible, and capable of such extensive power and variety of motion-so exquisitely sensible, also, as in man. We find no distinct and accurately formed fingers, covered with a soft cushion, composed almost entirely of one mass of nervous fibres, and a network of vessels. On the contrary, in all animals in which even an approach to the human hand is discovered, we find this organ ill-shaped, or indistinctly divided, the fingers are not tapering, nor protected by a broad expanded nail;-this is constructed in such, for retaining or lacerating, rather than for serving as a defence to the multitude of nerves, with which the fingers in man are so abundantly supplied.

It may not, perhaps, be foreign in this place to remark, that the presence, absence, and relative perfection of the clavicle, or collar-bone, in animals, furnishes a characteristic mark of the de

gree of motion enjoyed by the arm, (as we venture to call it,) and consequently, of an organ of greater or less similitude to the human hand, as it regards use and sensibility. For example: in the horse, cow, &c. the motion of the forelimbs is confined, being merely progressive-in these the clavicle is wanting, and their foot bears not the slightest resemblance to the hand, either in configuration or sensibility. But, on the contrary, in the ape we find a perfect clavicle, and an arm and hand differing but in a few points from the human, and enjoying perfect freedom of motion. In the squirrel, the mouse, and others, the clavicle, though existing, is imperfect; the hand bears a much more distant resemblance to the human; the power of rotatory motion in the arm is more circumscribed; the nails are formed for seizing and retaining, and the sensibility of the hand is inconsiderable. Below these animals, are the feline tribe ;-the cat, for instance, has a still less perfect clavicle, and the motion of the fore-limbs is still more limited, while the foot or paw, (for here it cannot be called hand,) incapable of holding or grasping objects, as in the squirrel, is furnished with nails, destined to seize and lacerate. Thus do we find, among the inferior mammalia, according to the perfection or absence of the clavicle, a nearer or more distant approach to the human arm and hand in shape, sensibility, and power of motion.

The sense of touch, properly so called, is enjoyed universally by the skin or integument surrounding and enveloping the frame; but, as we have intimated, not by every part of it in the same accurate degree of perfection; for as this depends, in a great measure, on use and habit, (supposing also a nicer organization,) where it is the most exercised in a way accordant with nature, it will, of course, be the most perfect.

The term skin is employed to designate a texture, composed of three membranes, differing from each other in use and composition. These are the

cutis vera, or true skin; the rete mucosum, or mucous web; and the epidermis, external membrane, or cuticle. The cutis vera is a texture formed almost entirely of vessels and nerves, at least they are distributed most abundantly throughout its whole composition. Here, numerous minute arteries terminate in exhalants,-here the absorbent system commences, and the nervous filaments end. If this membrane be accurately examined, multitudes of small papillæ or eminences are found arising from its surface, disposed in regular order, but varying in different parts in shape and magnitude these are the pulpous extremities of the nerves, thus elevated, for the purpose of increasing their power of perception, and surrounded by a web of the most exquisite fineness. In those parts where the sense of touch is most exercised and in the highest perfection, as in the hand and tips of the fingers, these papilla are the most distinct and elevated. Over this cutis vera is spread the rete mucosum, so called from its gelatinous consistence and net-like structure, being perforated universally by the exhalant vessels, absorbents, and nervous papillæ. The principal use of this delicate web seems to be, to preserve the nerves in a state of moisture, favorable to their sensibility and action.

In all climates the color of the rete mucosum is found to vary; but from what cause it is difficult perhaps to determine. In the negro it is black; in the American, copper-colored; in the Asiatic, tawny or olive; and in the European, from a darkness almost equal to the negro, to a white; in fact, it would seem, that as we recede from the temperate climes to the tropic, or to the pole, the skin gradually assumes a darker hue, till, under the equator at least, it becomes completely black.

The rete mucosum we have stated to be gelatinous; and to prevent the evaporation of moisture, and preserve it in its natural state of humidity, it is entirely covered by the epidermis,

or cuticle. This is a thin, transparent, and insensible membrane, being supplied neither with nerves nor vessels of any description. If minutely examined, it is found to be abundantly perforated in every part by the orifices of the exhalants and absorbents, commonly called the pores; but besides preventing evaporation, the use of the epidermis is also to cover the nervous papillæ, and thereby moderate the sensation, too vivid, and amounting to pain, which the actual contact of even the most delicate bodies would produce. When removed, as by blisters or scalding water, the epidermis is quickly reproduced, but by what precise process, is still doubtful.Some animals shed the cuticle periodically, entire like a sheath, as serpents; from other animals, it is thrown off in the form of scales or dust, a new cuticle being previously prepared. Besides these natural changes, it undergoes others, as thickening from pressure, which we may observe in the palms of the hands, or soles of the feet, sometimes assuming the consistence of horn.

The cuticle offers a variety of appearances in different animals, from a texture soft and delicate, and even like mucus in some aquatic animals, to scales, shells, and plates, constituting a natural armor.

These are the membranes composing the skin; but besides this, there is universally or partially between it and the muscles, in most animals, what is called the cellular membrane. This is a tissue composed of membranous cells, formed by the crossing of the membranes in all directions, and serving as the receptacle for the fat. Its use appears to be to weaken the impressions of external injuries, and protect against the effect of changes of temperature in the surrounding element; but especially to serve as a magazine for the deposition of the superabundant nutriment which the system is supplied with, to be reabsorbed as the wants of the body may require.

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