other; and if they were preceded or accompanied by the sound of a bell, then any one of these sensations, the taste, or the smell, or the sound, would recal the others.

If a number of sensations were frequently repeated in the same order, such as the various modifications of sound forming a tune, they would be recalled in the same order. By frequent hearing of a tune, the whole sounds of the tune may be recalled in the same order, while no two of them may be recalled in the reverse order. Perfect familiarity with a piece of music does little to enable us to perform, or remember it backward.

Hence we may learn the importance of observing a certain order, so far as it is practicable, in the fulfilment of all necessary duties. By the repetition of them in the same order of succession, each as it is finished will suggest that which is to follow, as every note of a tune suggests its successor. Whereas, if one duty sometimes precedes, and sometimes follows another, and, consequently, each is sometimes followed by one, and sometimes by another duty, some must always be in danger of being omitted.

This power, or capacity, or aptitude of the mind for having past sensations renewed is called memory, and the reviving or renewing the sensations is called remembering them, for memory is never exercised but according to those laws by which past sensations are recalled. These laws are sometimes called laws of association, or, more correctly, the laws of suggestion. As memory is the power or aptitude of the mind for having its past sensations recalled or revived, so the laws of suggestion are the laws by which recals or revivals of sensations take place.

We have spoken of sensations recalled as if the sensation itself were repeated; but there is a wide dif ference between a past sensation being revived in the mind and a similar sensation being excited by the same

external object affecting the organs of sense. Thinking of or remembering anything that we have seen or heard is very different from seeing or hearing it again. The amount and nature, however, of the difference between an original sensation, and the same sensation remembered, is not very easy to determine. Much of the indistinctness of remembered sensations, when compared with the original sensations, is doubtless to be ascribed to the multitude of different objects which during our waking hours are operating on the organs of sense, and, as it were, soliciting our attention; for however intent we may be on any remembrance, present objects are seldom or never excluded from all share of our attention. But when external objects are absolutely excluded, as in sleep or in waking reveries, remembered sensations sometimes assume much or all of the distinctness of reality. Yet, even in these cases, we question whether the remembered sensation is ever so vivid as the original one. We may be impressed with the reality of the objects that occupy the mind in dreams, but that is because they are not brought into contrast with original sensations; but it does not follow that they are in any case so vivid as original sensations. The pain of a toothache remembered in a dream is very different from an actual repetition of the pain. The one would probably awake us; the other, although we believe it for the time to be real, permits us to sleep on. We sometimes say that we remember a transaction or event at which we were present as distinctly as it appeared when we witnessed it; but this is always, we apprehend, either figurative or erroneous language. It is a wise provision that there should be a clear, distinguishable difference between actual sensations and the remembrance of them, either when asleep or awake; for were it otherwise, it would be impossible to distinguish between real transactions and the remembrance of them, and the boundaries between truth and falsehood or fiction, would be thrown

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into uncertainty. Nor are we quite certain whether the habit of lying, in some instances, may not have arisen from a state of mind by which former sensations are recalled with more than usual vividness, so that the story tellers have mistaken their dreams or waking reveries for realities, and repeated them as if they were 80. We remember one of the most truthful persons whom we ever knew describing in glowing terms the sensations he experienced from taking a mustard-vomit when he was a boy-the torture of it, as if it had been liquid fire that was passing down his throat. His elder brother, a man of equal probity, who was present, said to him, "You altogether forget, it was not you who took the mustard-vomit, but myself, and you heard me describe the effects in those very words; and they seem to have made such an impression upon you that you have come to imagine that it was you who experienced the sensation." They were both convinced that no second mustard-vomit had been administered, and the point was settled by the younger brother being satisfied that it must have been as the elder brother explained it. This, although not exactly a case of remembered sensation, is sufficiently near it to illustrate the supposition that men may mistake remembrances or imaginations for realities.

There are, it would appear, affections of the brain in which objects are recalled even in waking hours with much of the distinctness of reality. We have read, in the "Percy Anecdotes," (vol. xi., p. 3,) a narrative which bears upon it the marks of truth, that will illustrate this subject. M. Nicholai, a member of the Royal Society of Berlin, presented the narrative to that institution. He states that he had been under some great anxiety and distress of mind for a considerable time. When he was one day, in 1791, sitting in a room with his wife and another person, he saw suddenly standing before him, at the distance of about ten paces, a person whom he knew to be dead. M. Nicholai was of course greatly agitated.

He pointed to the spectre, and asked his wife if she did not see it. But she saw nothing. The figure, after remaining seven or eight minutes, vanished. In, the afternoon it appeared again, when he was alone. He was again greatly alarmed, and joined his family in another room; but thither the figure pursued him, sometimes present, sometimes vanishing. About two hours after this, several other stalking figures appeared. Similar appearances occurred again and again, sometimes of living and sometimes of deceased persons, till he became familiar with them, and able calmly to examine them. Sometimes several persons would appear to him at the same time, talking to him or to one another, in the presence of his family, and he could converse with his family respecting them, tell them who they were, and what they were saying to him. He observes, that he could always distinguish these spectres from real persons present. They would appear to open the door and enter the room, but he never mistook a real person entering the room for one of these illusions. The distinction between these appearances and realities, he observed, was, that the colours of the former were less vivid and distinct than those of the latter. The general course of their conversation to him was condoling with him on the cause of his distress. At length he was so constantly haunted with them, the whole space around him appearing to be filled with them, even when he was walking in the street, crowding upon him, and talking to him, that he resolved upon having his head leeched. While this operation was going on, the whole room seemed crowded with these spectres of his imagination. But some hours afterwards they appeared to move more slowly, their appearance became more faint, they first lost all colouring and became white; then parts of them began to disappear, leaving only imperfect parts of figures remaining, till the whole illusion, finally, was obliterated; and at the time when he wrote the account of his case,

which was a considerable time afterwards, he had had no return of it.

This narrative may help to explain many of the stories of ghosts, second sight, &c., which are always most prevalent in an unsettled state of society, when the minds of people are kept in constant excitement and dread; and the best-recorded instances of their appearance have been under circumstances calculated to excite and agitate the minds of those who are reported to have seen them. The faintness of the colouring, also, and the disappearance of all colour, and also the mutilated figures seen by this gentleman as the disease was subsiding, may account for apparitions being represented as always pale and dressed in white, and also for the imperfect forms in which they are reported to have appeared. Abercrombie mentions a lady who, while recovering from a debilitating fever, was visited daily by the spectre of a deceased friend. As she regained strength, the appearance became fainter and fainter, till it disappeared. Professor Alison

mentioned in his lectures, that, after a fatiguing day, he would see numbers of faces looking at him through the curtains. These visions were not unpleasant. They were never the faces of persons he knew. A farmer mentioned to a friend that one of his shepherds, an old man, used to see cattle going in rows at a distance from him; that, until he discovered the illusion, he had weary walks through the fields to drive the supposed animals out of the corn.

But what is most directly to our present purpose is, that this case, as well as the phenomena of memory, waking or sleeping, seems to indicate that remembered sensations differ from real sensations chiefly in this, that the remembrance of a sensation is sufficiently distinct to enable us to identify it as the reviving of the original sensation, yet is never so strong or vivid as the direct effect of the object of sense upon the sensory organs. That the remembrance of sensations, however,