destroyed, no sensation can be produced: where there are no nerves, there is no sensation: where the nervous branches are most numerous, there is most sensation: if the nerve be destroyed, sensation cannot be produced from those parts to which the nerve belongs, which are further from the brain than the injured parts. The brain is the ultimate organ of sensation of which we have any knowledge All the nerves terminate in the brain. If the brain is compressed, sensation is suspended. If the brain is considerably injured, sensation ceases-So, also, there is considerable reason to believe that the brain is the immediate organ of ideas. If the brain is diseased, many of the phenomena of thought are altogether changed; if the brain is compressed, thought is suspended; if the brain is injured, ideas cease. So, also, the brain appears to be the ultimate organ of all motions which are not produced by the immediate action of external objects upon the muscles. The muscles are the immediate organs of motion. The muscles consist of fleshy substances, and sometimes of tendons. The tendons fasten the muscles to the bones; and the fleshy part by its contrac tions produces the motions of the bones. Into the fleshy parts of the muscles numerous nerves enter; they are diffused over its surface and within its substance. These nerves, as before mentioned, terminate in the brain either of the head or back. They are the intermediate organs of voluntary motion between the brain and the muscles. If a nerve be compressed or punctured, motion is produced in the muscle over which that nerve is distributed. If a portion of a nerve be cut, or otherwise destroyed, voluntary motion can no longer be produced in that muscle over which it was distributed. If the brain be touched with any instrument or caustic, applied to it, the muscular system undergoes the most violent contortions. If the spinal marrow be pierced with a probe, all the muscles of the trunk and limbs undergo violent contortions, particularly those of the back. If the brain be compressed, the whole body becomes paralysed, and the power of voluntary motion is suspended. If the spinal marrow be compressed, the power of voluntary motion is suspended in those muscles which receive their nerves from the back. If the brain is considerably injured, all power of voluntary motion ceases.

The external organs of sense are usu ally classed under five heads, those of sight, of hearing, of feeling, of smell, and

of taste. The sense of feeling might probably be divided with convenience into two or three, because the classes of sensations, which are referred to this sense, differ considerably in themselves and in the external causes producing them. But the common arrangement is sufficient for our purpose.

By the law of association, many ideas received directly from sensible objects, through the medium of different senses, become connected, and at last blended together, so as to form one very com plex, though apparently uncompounded, idea; and this complex idea is often recalled to the mind by a corresponding sensation, and, by association, becomes so connected with that sensation, that the complex idea itself is often mistaken for a part of the sensation. For instance, the sensation produced by the impression made by a globe on the sense of sight is, as can be proved, nothing more than that produced by a circle, with certain variations of light and shade; yet, immediately on the sensation being perceived, the ideas of its solidity, of its hardness, its magnitude, and of its being something external to one's self, (all of which have been derived from the sense of touch, in connec tion with this object, or others in some respect similar), immediately rise up in the mind in one blended form; by their complete coalescence they appear to be one, and by their immediate and constant connection with the sensation, they appear to the mind as a part of the sensation. Indeed, there are comparatively few people, who ever think that the sensation derived from the sight is nothing more than that derived from a minute picture delineated on the back part of the eye, called the retina. Things appear to us, at one glance of the sight, to be solid or flat, to be near or distant, to be large or small, to be conjoined with other things, or separate from them, to be parts of our own frame, or external to it, &c. and all this we appear to learn by the sight alone; but the fact is, that all these ideas are derived from another sense, at various times, and altoge ther blending together, and arising the moment the visible impression is communicated, they appear part of the visible impression. "The visible appearance of objects," as Berkeley observes, "is a kind of language, serving to inform us of their distance, magnitude and figure;" no sooner are these signs presented to the mind, than with the rapidity of lightning the ideas associated with them succeed, and appear to have been communi

cated by the sight, and to be in reality a part of the sensation.

The sensation thus connected with the complex idea is a perception. The accuracy and vividness of the sensation depend entirely upon the sensitive power and its organs: the accuracy and vividness of the perception depend partly upon the accuracy and vividness of the compo. nent sensations, and partly upon the activity and energy of the retentive and associative powers.

For a somewhat particular account of each sense, with statements respecting the share each has in forming our ideas, i. e. our notions and our feelings, we beg our readers to refer in this place to the following articles, in the order in which we here detail them; SIGHT, TOUCH, TASTE, SMELL, and SOUND; and presuming upon the perusal of those articles, we shall here make a few general observations respecting sensations.

1. Sensations are the rudiments and elements of all our ideas; that is, of all our thoughts and feelings. This is a position, which perhaps few of those who are unacquainted with the speculations of metaphysical writers would suppose to have been ever doubted. When an infant enters into the world, there is no appearance of any ideas being in its mind; and no one can doubt that if any human being could be deprived of all his organs and sensations, before any sensations had been received, that he would never have ideas. Yet it was once generally believed, that there are in ever human being ideas born with him, which were called innate. What they were, or in what respects they differed from those which are indisputably received by means of the organs of sensation, was never, we apprehend, pointed out. Indeed, the doctrine of innate ideas rests merely on an appeal to ignorance; and as soon as any probable account of their origin is given, all support of it falls at once. Before the grand law of association was tolerably understood, the mode of the formation of many complex ideas could not be satis factorily ascertained; and it must still be admitted, that we cannot in all cases fully trace the formation of our complex ideas; but we can in a sufficient number to decide the point. Between those whose formation we can explain, and those whose we cannot, there is no further difference, than our greater or less acquaintance with the individual steps of the process.

2. In the earliest exercise of the sensitive power, sensations are simple, un

compounded with the relics of former corresponding sensations; but the sensations very soon become perceptions, that is, they instantaneously recal the relics of other corresponding sensations. This implies the exercise of the retentive and associative power; but as perceptions are almost uniformly produced by every exercise of the sensitive power, it may be proper to speak of them here in connection with sensations. That sensations in a somewhat advanced state of mental culture are usually perceptions, any person may satisfy himself, by considering, that sensations are usually accompanied either with an idea of an external object causing them, or (if they are thereby the effect of the state of the bodily system) with an idea of the sen sation being in the part of the body in which the cause of the sensation exists; both of which are complex ideas, formed from a great number of impressions, and which could in no instance be produced by any exertion of the sensitive power. -We, therefore, in many cases, without any impropriety, speak of perceptions and sensations indiscriminately; since a perception always implies a sensation, and sensations most frequently are perceptions; and accordingly we shall find, in some writers, that they are confounded sometimes where they ought te be kept distinct.

3. Considering man as an intellectual being, the accuracy and extent of his perceptions are of the first moment. They are, in fact, the materials of all knowledge respecting external objects, and in the early stages of mental culture are the only objects of the understanding. Now the accuracy and extent of the perception depends upon the vivid. ness and efficaciousness of the component sensations, and the number of them received from the same or similar objects in different situations, and through the medium of different senses. The object, therefore, of the early education of the human being should be, to invigorate the organs of sense. Independently of the effects of the general healthiness of the system, it appears decidedly probable, that the organs of sense are capable of being improved by exercise. It is the grand law of our frame, that moderate exertion increases the power of exertion; and assuredly there are facts which lead to the same conclusion in this particular case. But this may be safely left to the natural effect of exertion. All that is to be done is, to afford children the opportunity of exercising their senses on a va

riety of objects, and as much as possible in a variety of situations. Some have supposed that the senses are not capable of improvement. We readily grant, that the superiority possessed by some over others, in the use of their senses, principally consists in the extent, and accuracy, and vigour of their perceptions. Two persons, with equally good eyes, will see the same thing very differently, will have very different perceptions, though the sensations cannot as far aswe can judge, differ in any respect. Let two such persons have a watch placed before each of them, as nearly as possible in the same situation in every respect; suppose one minutely acquainted with the beautiful machine and the other unacquainted with it; they have the same sensations, but how different their perceptions; one sees a number of movements, of which he cannot discern the connection, nor point out the part it bears in the performance of the object; the other at once perceives the mutual dependence of the parts, and the minutia of the whole structure, its excellencies and defects, &c. Our limits will not permit further illustration, but it is in the power of every one to trace it for themselves, by recollecting how differently the same thing appears to different persons of equally vigorous powers of sensation, and how differently it appears to the same person at different times. But all these things do not disprove what we before stated respecting the improvement of the senses them selves; they merely point out, as another means to render sensation efficacious, that we should extend the perceptions, and render them accurate. This is, by giving extent and accuracy to the perceptions, we render the sensations more efficacious, which we mentioned as one of the principal things upon which the extent and accuracy of the perceptions depend. To give vividness and efficacy to the sensations, the organs of sense should then be exerted on various objects and in various situations; a still more important mean is, to direct the attention sufficiently to the objects of sensation. In what manner it produces the effect we know not, but it is certain that the efficaciousness of sensations in producing distinct ideas depends principally upon the degree of attention which those sensations receive. Hence, those who have the care of infants and children should give them every opportunity to keeptheir attention directed to the objects of their senses, and every means should be employed to lead them to such attention:

a child intently gazing upon an object, or examining it with its little hands and lips, is as usefully employed in the cultivation of intellect as the fondest parent can wish. There is, however, more to be done in this connection, also, by allowing the child full scope for its own exertions, than by any direct efforts which can be made by others. When its attention is fixed, let it remain so; if possible, let the objects of sense be brought under different aspects, and exposed to the different senses. Before words become to a child the sign of voluntary action, all that can be done is, to expose it to sensations, and to allow them to fix the attention: but afterwards more direct efforts may be made, and the attention may be fixed by various other means than the mere action of the sensations themselves Independently of its value in providing materials for clear perceptions, it is of peculiar importance to the future improvement of the understanding, and consequently to the moral culture, that the habit of fixed attention should be acquired; and we wish here to express our decided opinion, that the character of the intellect and affections, however much it may be modified by future cultivation, receives its stamp from the employment of the first few years of life; that the education of the nursery is of almost incalculable moment in the mental and moral culture; that by neglect of it, years of labour may be rendered requisite to compensate in some degree for it, and by a proper attention to it, a foundation is laid for a clear and vigorous understanding, and lively and pure affections. As far as the understanding can be considered as separate from the affections, the primary object is, to gain clear and extensive perceptions, and fixed active attention; and respecting these the few observations which have been made may afford some useful hints to the thoughtful. Miss Hamilton has many judicious remarks on this subject, at the beginning of the second volume of her work on education; a work, which, though sometimes incorrect as to scientific arrangement, and still more frequently as to precision of language, contains many highly valuable instructions for the culture of the human mind.

4. Sensations are to be considered, not only as the original materials for the various operations of intellect, but as the sources of all the mental pleasures and pains. In the earliest periods of life, probably there is no sensation unaccompanied either with pleasure or with pain; and as man is constituted, this is neces

sary, both to fix the attention upon the objects of sense, and for self-preservation. Pleasurable sensations are called sensible pleasures, painful sensations sensible pains. The pleasurable sensations leave behind them pleasurable ideas, which are called mental or intellectual pleasures; and in the same manner the painful sensations leave behind them painful ideas, which are called mental pains. Mental pleasures combine with one another, and form more complex feelings, and these with others, and so on till, owing to the very great complexity of the whole, the component parts are not discernible. In this stage of their progress it is that they generally fall under our inspection. They appear to us at first to have no connection with sensations; but this is merely because we cannot readily separate them into their component parts. Reasonable evidence can be adduced to show, that all the mental pleasures and pains have their origin, indeed are formed solely of the relics of sensible pleasures and pains.

5. Considering sensible pleasures and pains as the rudiments of mental pleasures and pains, it is requisite, during the early part of life, to keep the inlets of sensation in a fit state for receiving them, and not to check the one, or to impose the other, except where an enlightened regard to the future welfare requires it. The health of the body should be attended to, not merely as a means of present and future sensible enjoyment, but as increasing the fund of materials for the purest mental pleasures. Childhood should be regarded as the time for the acquisition of materials, not only for the intellect, but for the affections. Its pleasures should be restrained only by those limits which the laws of sensation and association impose; which require that they should be moderate, and connected only with such objects as will not lead to future pains: its unavoidable pains should, as far as possible, be removed; and no avoidable ones imposed, except what the laws of association require, that is, those which are necessary for the removing or preventing of greater evil, either by remedying bodily disorders, and destroying false associations, or by connecting sensible pains with such objects as would lead to future pains, more important either as to vividness or duration.

6. The grand law of sensible pleasures and pains is, that by frequent repetition they lose their vividness. This is a law, to which may be traced various important facts connected with the moral culture. VOL. XI.

Whatever be the peculiar mode by which impressions from the objects of sense are transmitted through the nerves to the brain, it seems decidedly probable, that the difference between pleasurable and painful sensations consists (as far as respects the sensations themselves) in degree only that pain has the same cause as pleasure, except that it acts more intensely. "All pleasure," as Hartley remarks, "appears to pass into pain by increasing its cause, impression, duration, sensibility of the organ upon which it is impressed, &c.: thus an agreeable warmth may be made to pass into a troublesome or burning heat, by increase or continuance; and the same thing holds with respect to friction, light, and sound." Hence, since repetition diminishes the vividness of the sensation, (provided there be no increase in the exciting cause, or in the sensibility of the organ, &c.) great pain will by repetition gradually subside into pain less intense; pains may be converted by repetition into pleasures, and pleasures may be converted into indifferent sensations. This progress may be observed in the effects of spirituous liquors, or any other stimuli, which strongly affect the organs of taste. There are probably no cases in which the taste of spirituous liquors would originally be otherwise than disagreeable; by degrees the repeated use of them brings the sensations which they occasion within the limit of pleasure; even then a considerable increase of the quantity taken would heighten the sensations to the limits of pain; but suppose the pleasurable portion continued without increase, the repeated use of it diminishes the vividness of the pleasure, till at last the sensation produced is completely indifferent.-We here adduce the fact merely as illustrative of the general principle.

7. We have stated, in the separate articles above referred to, that the original sensible pleasures derived from the taste and smell are very numerous, and far exceed the pains; that the original sensible pleasures derived from the sight and the hearing are also numerous, while the original sensible pains are few; and that the original sensible pleasures derived from the sense of feeling are less intense than the pains derived from that sense, which are more numerous and vivid than all the other sensible pains united. From this account we should be led to infer, that the pains of sensation are very far exceeded by the pleasures of sensation.—

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'This will be still more evident, when we recollect that the pleasurable sensations are those of constant occurrence: the painful sensations much more rare. In the early part of life, most sensations that are not painful are pleasurable; and the pleasurable are continually recurring. The eye and the ear seem to convey scarcely any thing but pleasurable sensations to the infant mind; the taste and smell are continually pouring in their pleasurable sensations, seldom mixed with pain; the feeling, when the body is healthy, "when life is felt in every limb," is also constantly adding to the stock of pleasurable sensations, those derived from the glow of health and the active motions of childhood; to balance all this, there are, in some few cases, frequent pains of body; but more frequently the pains arising from ill health, are of seldom recurrence, and the artificial sensible pains are still less frequently received. Such is the matter of fact; and if we consider the cause of the sensible pleasures and pains as differing only in degree, we shall readily admit, that, on the whole, the pleasurable sensations very far exceed the painful sensations; for the sensible pains being produced by an excessive action of the organs of sensation, common impressions will not produce them, and should they become very frequent, by the grand law of sensation, already stated, they will gradually diminish in vividness, and at last come within the limits of pleasure.

SENSITIVE plant. See MIMOSA. SENTICOSÆ, in botany, the name of the thirty-fifth order in Linnæus's Fragments of a Natural Method, consisting of the rose, bramble, and other plants that resemble them in external structure.

SEPIA, in natural history, cuttle-fish, a genus of the Vermes Mollusca class and order. Body fleshy, receiving the breast in a sheath, with a tubular aperture at its base; eight arms, beset with numerous warts or suckers, and in most species two pedunculated tentacula; head short; eyes large; mouth resembling a parrot's beak. Eight species are mentioned. They inhabit various seas, and in hot climates grow to a very considerable size; they are armed with a most terrible apparatus of holders, furnished with suckers, by which they fasten upon and convey their prey to the mouth.

S. octopus is found in the Mediterranean and Indian Seas, and in the latter it is sometimes so large that the arms are said to be nine fathoms long. In these seas the Indians never venture out without

hatchets in their boats, to cut off the arms, should it attempt to fasten upon them and draw them under water.

S. officinalis inhabits the ocean, and is the prey of the whale tribe and plaise; its arms are also frequently eaten off by the conger-eel, and are reproduced. See REPRODUCTION. The bony scale on the back is that which is sold in the shops, and which, when reduced to fine powder, is reckoned excellent for the teeth, as well for keeping them white as for preserving them. It is also used as pounce. These animals have the power of squirting out a black fluid resembling ink, which is said to be an ingredient used in the composition of Indian ink. They deposit their eggs upon sea-weed, which resemble a bunch of grapes. When first deposited they are white, but when impregnated by the male they become black; they are round, with a little point at the end, and in each of them is inclosed a living cuttle-fish, surrounded with a gelatinous fluid. The flesh is used as food by the Italians.

SEPIARIÆ, in botany, the name of the forty-fourth order in Linnæus's Fragments of a Natural Method, consisting of many beautiful woody plants, both of the shrub and tree kind, most of which do not drop their leaves till nearly the time in which the new leaves begin to appear. Among the plants of this order are the fraxinus, or ash; jasminum, jessamine tree; ligustrum, privet; syringa, lilac.

SEPTAS, in botany, a genus of the Heptandria Heptagynia class and order. Natural order of Succulenta. Sempervivæ, Jussieu. There is but one species, viz. S. capensis, round-leaved septas, a native of the Cape of Good Hope.

SEPTEMBER, the ninth month of the year, consisting of only thirty days: it took its name as being the seventh month reckoning from March, with which the Romans began their year.

SEPTUAGINT, the name given to a Greek version of the books of the Old Testament, from its being supposed to be performed by seventy-two Jews, who are usually called the seventy interpreters, because seventy is a round number. The history of this version is expressly written by Aristeas, an officer of the guards to Ptolemy Philadelphus, the substance of whose account is as follows: Ptolemy having erected a fine library at Alexandria, which he took care to fill with the most curious and valuable books from all parts of the world, was informed that the Jews had one containing the laws