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there is no sensation: where the nervous branches are most numerous, there is most sensation if the nerve be destroyed, sen'sation 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 sensa tion 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 tendon. The tendons fasten the muscles to the bones; and the fleshy part by its contractions 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 usually classed under five heads, those of sight, of hearing, of feeling, of smell, and of taste. The sense of feeling might probably be di

vided 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, be come connected, and at last blended together, so as to form one very complex, 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 connection 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 sensa tion 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 altogether 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 communicated 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 depends entirely upon the sensitive power and its organs: the accuracy and vividness of the perception depends partly upon the accuracy and vividness of the component sensa tions, 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 sensa tions.

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 every 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 satisfactorily 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, uncompounded with the relicts of former corresponding

sensations; but the sensations very soon be come perceptions, that is, they instantaneously recal the relicts 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 percep tions, 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 sensation 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 to 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 ob jects of the understanding. Now the accuracy and extent of the perception depends upon the vividness 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 hu man 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 variety of objects, and as much as possible

in a variety of situations.-Some have sup-
posed that the senses are not capable of im-
We readily grant, that the
provement.
superiority possessed by some over others
in the use of their senses, principally con-
sists 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 as we 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 dif-
ferent 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 de-
pendence of the parts and the minutia of
the whole structure, its excellences and de-
fects, &c. Our limits will not permit fur-
ther illustration, but it is in the power of
every one to trace it for themselves, by re-
collecting how differently the same thing ap-
pears to different persons of equally vigo
rous powers of sensation, and how diffe-
rently it appears to the same person at dif-
ferent times. But all these things do not
disprove what we before stated respecting
the improvement of the senses themselves;
they merely point out as another means to
render sensation efficacious, that we should
extend the perceptions and render them ac
curate. That is by giving extent and accu-
racy to the perceptions we render the sen-
sations more efficacious, which we mention-
ed as one of the principal things upon
which the extent and accuracy of the per-
ceptions depend.—To givę 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 at
tention sufficiently to the objects of sensa-
tion. 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 keep their 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 how-
ever 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 pos-
sible let the objects of sense be brought
under different aspects, and exposed to
Before words become
the different senses.
to a child the sign of voluntary action all
that can be done is to expose it to sensa-
tions, and to allow them to fix the atten-
tion: 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. Inde.
pendently of its value in providing materials
for clear perceptions, it is of peculiar im-
portance to the future improvement of the
understanding, and consequently to the
moral culture, that the habit of fixed atten-
tion 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 em-
ployment 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 the 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 per-
ceptions, 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 arrange-
ment, and still more frequently as to pre-
cision 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
In the earliest periods of life
pains.
probably there is no sensation unaccom-

panied either with pleasure or with pain; and as man is constituted, this is necessary 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 discernable. 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 relicts 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 snch 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. 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.-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 paius 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 plea

sure.

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, cuttlefish, 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.

and Indian Seas, and in the latter it is some times 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 be come black; they are round, with a little point at the end, and in each of them is inclosed a living cuttle-fish, surrounded witli 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 Pto

S. octopus is found in the Mediterranean lemy Philadelphus, the substance of whose

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