one hundred times in the day, at intervals the most irregular, in that state, which is immediately followed by the feeling of hunger, the painful feeling,and the consequent desire of food, which has been found to relieve it,would of course be felt one hundred times in the day. The regularity, therefore, of the recurrence of this state of the nerves, is a phenomenon, which belongs to the consideration of the physiologist of the body, not of the physiologist of the mind, whose immediate office is finished, when he can trace any particular feeling of the mind to some affection of our organic frame, as its invariable antecedent; and who knowing, therefore, that the feeling of pain in any of our appetites, is the effect or result of some organic affection, is not surprised that it should not recur, when that organic affection has not previously taken place,-any more than he is surprised that we do not enjoy the fragrance of roses or violets, when there are no particles of odour to be inhaled by us; or do not listen to songs and choral harmonies, when there is no vibration to be transmitted to the auditory nerve. It is at certain regular periods, that the full light of day, and the twilight of morning and evening, are perceived by us. But we do not think it necessary, on this account, to give any peculiar name to these visual perceptions, to distinguish them from others less regular, because we know, that the reason of the periodic recurrence of these perceptions, is that the various degrees of sunshine, which produce them, exist only at such intervals. We are hungry, when the nerves of the stomach are in a certain state; we perceive the sun, when the organ of vision is in a certain state. It is as little wonderful, that we should not have the feeling of hunger, except when the nerves of the stomach are in this state, as that we should not have the perception of the meridian sun, when the sun itself is beneath our horizon.

Since the mere pains of appetite, however, most important as they truly are, for the ends which they immediately answer, are yet of little importance in relation to our general knowledge, it is unnecessary to dwell on them at length. But I cannot quit the consideration of them, without remarking that admirable provision which the gracious Author of Nature has made by them, for the preservation not of our being merely, but of our well-beingof that health and vigour, without which, a frail and feverish existence, at least in its relation to this earthly scene, would be of little value. The daily waste of the body requires daily supply to compensate it; and if this supply be neglected, or be inadequate-or, on the other hand, if it be inordinately great, disease is the necessary consequence. To preserve the medium, therefore, or at least to prevent any very great deviation from it, He, who planned our feelings and faculties as well as our bodily frame, has made it painful for us to omit what is so important to life; and painful also to prolong the supply in any great proportion, after the demands of nature have been adequately satisfied. If food had afforded gratification only as relieving the pain of hunger, these natural boundaries of appetite would have required no aid from moral or physical lessons of temperance. But the indulgence of nature, in conferring on us the sense of taste, and making food a luxury as well as a relief, we abuse, as we abuse her other kindnesses. The pleasures of this most intemperate of senses, may lead, in some degree, beyond the due point of supply, the greater number of mankind; and may drive, to excesses more injurious, all those herds of unthinking sensualists who prefer the sickly enjoyment of an hour, to the health and virtue, and intellectual as well as physical comfort, of more frugal repasts. Yet even to them, nature

points out in the feeling of satiety, where intemperance begins, or where it has already begun; and if they persist, notwithstanding this feeling, how much more would they be in danger of over-loading the powers of life, if there had been no such feeling of growing uneasiness, to suppress the avidity of insatiable indulgence.

"Though a man knew," says Dr. Reid, "that his life must be supported by eating, reason could not direct him when to eat, or what; how much, or how often. In all these things, appetite is a much better guide than reason. Were reason only to direct us in this matter, its calm voice would often be drowned in the hurry of business, or the charms of amusement. But the voice of appetite rises gradually, and, at last, becomes loud enough to call off our attention from any other employment."*

If indeed, the necessary supply were long neglected, the morbid state of the body which would ensue, though no pain of actual hunger were to be felt, would convince, at last, the sufferer of his folly. But the providence of our Gracious Creator, has not trusted the existence of man to the dangerous admonition of so rough a monitor, which might, perhaps, bring his folly before him only when it was too late to be wise. The pain of hungerthat short disease, if it may be so termed, which it is in our power so speedily to cure, prevents diseases that more truly deserve the name. Between satiety on one side, and want on the other, the stream of health flows tranquilly along, which, but for these boundaries, would speedily waste and disappear; as the most magnificent river, which, if dispersed over a boundless plain, would flow almost into nothing, owes its abundance and majestic beauty to the very banks that seem to confine its waters within too narrow a channel.

Besides those particular feelings of bodily uneasiness, which, as attended with desire, constitute our appetites, there are other affections of the same class, which, though not usually ranked with our external sensations or perceptions, because we find it difficult to ascribe them to any local organ, are unquestionably to be arranged under the same head; since they are feelings which arise, as immediately and directly from a certain state of a part of the nervous system, as any of the feelings which we more commonly ascribe to external sense. Of this kind is that muscular pleasure of alacrity in action, which forms so great a part of the delight of the young of every species of living beings, and which is felt, though in a less degree, at every period of life, even the most advanced; or which, when it ceases in age, only gives place to another species of muscular pleasure-that which constitutes the pleasure of ease the same species of feeling, which doubles, to every one, the delight of exercise, by sweetening the repose to which it leads, and thus making it indirectly, as well as directly, a source of enjoy

ment.

In treating of what have been termed the acquired perceptions of vision, which are truly what give to vision its range of power, and without which the mere perception of colour would be of little more value than any other of the simplest of our sensations, I shall have an opportunity of pointing out to you some most important purposes, to which our muscular feelings are instrumental; and in the nicer analysis which I am inclined to make of the perceptions commonly ascribed to touch,-if my analysis be accurate-we shall find them operating at least as powerfully. At present, however, I

"On the Active Powers, Essay III. c. 1.

examination which it received, it is unnecessary to dwell at any length on the other objection, drawn from changes of general character, in the same individual, at different periods of life, or in different circumstances of fortune; since precisely the same arguments, from the general analogy of nature, which disprove the supposed incompatibility in the one case, disprove it also in the other. Even matter itself, we have seen, may, without the slightest alteration of its identity, exist in an almost infinite variety of states; having, in some of these states, qualities precisely the reverse of those, which it exhibited in other states, attracting what it repelled, repelling what it attracted; and it surely is not more wonderful, therefore, that the same identical mind, also, should, in relation to the same objects, in different circumstances, be susceptible of an almost infinite variety of affections,-approving, disapproving, choosing, repenting. If we knew nothing more of the relations of two billiard balls to each other, than the phenomena which they exhibit, in the moment of their mutual percussion, when they have been forced, within a certain degree of close vicinity, by the impelling stroke, we should regard them, from their instant reciprocal repulsion, as having a natural tendency to fly off from each other; and, in the state in which they then exist, there is no question that such is their tendency,-a tendency, which, in these circumstances, may be regarded as their genuine physical character. Yet we have only to imagine the two balls placed at a distance from each other, like that of the remotest planet from the sun; and, in traversing the whole wide void that intervenes, what a different physical character would they exhibit, in their accelerating tendency toward each other, as if their very nature were lastingly changed? If there are, then, such opposite tendencies in the same bodies, without any loss of identity, why may not the same minds also have their opposite tendencies, when, in like manner, removed, as it were, into circumstances that are different, loving, perhaps, what they hated before, and hating what they loved? If the change of state be not temporary, but permanent, the resulting affections may well be supposed to be permanently different; and, indeed, if they be different at all, cannot but be permanently different, like the altered state. It is as little wonderful, therefore, when any lasting change of circumstances is taken into account, that the same individual should no longer exhibit the same intellectual and moral appearances, as that matter, in its different states, should no longer exhibit the same obvious phenomena, attracting, perhaps, the very bodies which it before repelled, and repelling the very bodies which it before attracted, and attracting and repelling with differences of force, and consequent differences of velocity in the bodies moved, the varieties of which it would require all the powers of our arithmetic to compute.

When we observe, then, in a mind, which we have long known and valued, any marks of altered character,-when, for example, in one, who, by the favour, or rather by the cruelty of Fortune, has been raised, from a situation comparatively humble, to sudden distinctions of power and opulence, we see the neglect of all those virtues, the wider opportunity of exercising which seemed to him formerly the chief, or even the only, advantage that rendered. such distinctions desirable,-the same frivolous vanity, which before appeared to him ridiculous in others, and the same contemptuous insolence of pride, which before appeared to him contemptible,-a craving and impatient desire of greater wealth, merely because he has no longer any use to make of it, unless, indeed, that it has become more necessary to his avarice, than it ever

was before to his want, and a gay and scornful indifference to miseries, that are still sometimes able to force themselves upon his view, the relief of which, that once seemed to him so glorious a privilege, would now not require of him even the scanty merit of sacrificing a single superfluity: when we perceive this contrast, and almost say within ourselves, Is this the same being? we should remember, that the influence of fortune is not confined to the mere trapping, which it gives or takes away,-that it operates within as much as without, and that, accordingly, in the case now imagined by us, the new external circumstances have been gradually modifying the mind, in the same manner, as new external circumstances of a different kind modify the bodies, which happen to be placed in them,—not affecting their identity, but altering their state; and that, if we could distinguish, as accurately, the series of changes, which take place in mind, as we can distinguish those which take place in matter, we should not be more astonished, that, in circumstances of rare and unhappy occurrence, a disposition once apparently generous is generous no more, than we are to observe a body, attracted to another body, at one distance, and afterwards repelled from it, in consequence merely of a change of their mutual position,-a change so very slight, as to be altogether undistinguishable by our senses.

I have dwelt on this question at much greater length than I should otherwise have done, however interesting it truly is as a question of metaphysics, because I was anxious to obviate a prejudice which is very closely connected with this point, and which, most unfortunately for the progress of the Philosophy of Mind, has given a wrong bias to the speculations of many very enlightened men. No one, I am aware, can be so sincerely sceptical as to doubt, even for a moment, his own identity, as one continued sentient being, whatever ingenious sophistry he may urge in support of the paradox which he professes to hold. But still, while the compatibility of diversity with absolute identity, as now explained to you, was but obscurely felt,—a compatibility which, to the best of my remembrance, no writer, with whom I am acquainted, has attempted to illustrate, the difficulty of reconciling the growth or decay of knowledge, and all the successive contrasts or changes of feeling, which our sensations, thoughts, emotions, exhibit, with the permanent indivisible unity of the same sentient principle, has been sufficient, in many cases, to produce a vague and almost unconscious tendency to materialism, in minds that would not otherwise have been easily led away by a system so illusive; and, where it has not produced this full effect, it has at least produced a tendency, in many cases, to encumber the simple theory of the mental phenomena with false and unnecessary hypotheses, very much akin to those of absolute materialism. Without this absolute materialism, mind must still be left, indeed, as the ultimate subject of sensation, and the difficulty truly remains the same; but it is contrived to complicate, as much as possible, the corporeal part of the process, which precedes this ultimate mental part, by the introduction of phantasms, or other shadowy films, animal spirits, vibratiuncles, or other sensorial motions, that a wider room may thus be left for a play of changes, and the difficulty of accounting for the diversity of sensations be less felt, when it is to be divided among so many substances in almost constant motion; while the attention is, at the same time, led away from the immediate mental change, in which alone the supposed difficulty consists, to the mere corpuscular changes, in which there is no supposed difficulty.

It is a general law of our internal, as well as of our external perceptions, that we distinguish most readily what is least complicated. In a chorus of many voices, a single discordant voice may escape even a nice discriminator of musical sounds, who would have detected instantly the slightest deviation from the melody of a simple air. A juggler, when he wishes to withdraw a single card, is careful to present to us many; and, though the card which he withdraws is truly before our eyes at the very moment at which he separates it from the pack, we do not discover the quick motion which separates it, however suspiciously watchful we may be, because our vigilance of attention is distracted by the number of cards which he suffers to remain. It is not because the card which he removes is not before us, then, that we do not observe the removal of it, but because it is only one of many that are before us. It is precisely the same in those complicated material processes, with which some theorists encumber the simple phenomena of the mind. The difficulty which seems, to them, to attend any diversity whatever in a substance that is identical, simple, indivisible, and incapable of addition or subtraction, remains, indeed, ultimately in all its force, and would strike us equally, if this supposed difficulty were to be considered alone. But many bypothetical vibrations, or other motions, are given to our consideration at the same moment, that glance upon our mental view like the rapid movements of the juggler's hand. We, therefore, do not feel, so painfully as before, a difficulty which occupies our attention only in part; and, in our feeble estimation of things, to render a difficulty less visible to us, is almost like a diminution of the difficulty itself.

For obviating this tendency to materialism, or to what may be considered almost as a species of semi-materialism in the physiology of the mind, it is of no small consequence to have accurate views of the nature of our mental identity. Above all, it is of importance, that we should be sufficiently impressed with the conviction, that absolute identity, far from excluding every sort of diversity, is perfectly compatible, as we have seen, with diversities that are almost infinite. When we have once obtained a clear view of this compatibility, as independent of any additions or subtractions of substance, we shall no longer be led to convert our simple mental operations into long continued processes, of which the last links only are mental, and the preceding imaginary links corporeal; as if the introduction of all this play of hypotheses were necessary for saving that identity of mind, which we are perhaps unwilling to abandon altogether; for it will then appear to us not more wonderful, that the mind, without the slightest loss of identity, should at one moment begin to exist in the state which constitutes the sensation of the fragrance of a rose, and at another moment should begin to exist in the state which constitutes the sensation of the sound of a flute, or in the opposite states of love and hate, rapture and agony-than that the same body, without the slightest change of its identity, should exist, at one moment, in the state which constitutes the tendency to approach another body, and at another moment in the opposite state which constitutes the tendency to fly from it, or that, with the same absolute identity, it should exist, at different moments in the different states, which constitute the tendencies to begin motion in directions that are at right angles to each other, so as to begin to move in the one case north, in the other east, and to continue this motion, at one time with one velocity, at other times with other velocities, and consequently, with other tendencies to motion that are infinite, or almost infinite.