hearing are met with, though less frequently than those of vision. A gentleman recently recovered from an affection of the head, in which he had been much reduced by bleeding, had occasion to go into a large town a few miles from his residence. His attention was there attracted by the bugle of a regiment of horse, sounding a particular measure which is used at changing guard in the evening. He assured me that this sound was from that time never out of his ears for about nine months. During all this period he continued in a very precarious state of health; and it was only as his health became more confirmed that the sound of the bugle gradually left him. In regard to ocular spectra, another fact of a very singular nature appears to have been first observed by Sir Isaac Newton,-namely, that when he produced a spectrum of the sun by looking at it with the right eye, the left being covered, upon uncovering the left, and looking upon a white ground, a spectrum of the sun was seen with it also. He likewise acquired the power of recalling the spectra, after they had ceased, when he went into the dark, and directed his mind intensely, "as when a man looks earnestly to see a thing which is difficult to be seen." By repeating these experiments frequently, such an effect was produced upon his eyes, "that for some months after," he says, "the spectrum of the sun began to return as often as I began to meditate upon the phenomena, even though I lay in bed at midnight with my curtains drawn."

II. Impressions of objects recently seen returning after a considerable interval. Various interesting examples of this kind are on record. Dr. Ferriar mentions of himself that when about the age of fourteen, if he had been viewing any interesting object in the course of the day, as a romantic ruin, a fine seat, or a review of troops, so soon as evening came, if he had occasion to go into a dark room, the whole scene was brought before him with a brilliancy equal

to what it possessed in daylight, and remained visible for some minutes.

III. False perceptions arising in the course of some bodily disorder, generally fever. A lady whom I attended some years ago, in a slight feverish disorder, saw distinctly a party of ladies and gentlemen sitting round her bedchamber, and a servant handing something to them on a tray. The scene continued in a greater or less degree for several days, and was varied by spectacles of castles and churches of a very brilliant appearance, as if they had been built of finely cut crystal. The whole was in this case entirely a visual phantasm, for there was no hallucination of mind. On the contrary, the patient had from the first a full impression that it was a morbid affection of vision, connected with the fever, and amused herself and her attendants by watching and describing the changes in the scenery. A gentleman who was also a patient of mine, of an irritable habit, and liable to a variety of uneasy sensations in his head, was sitting alone in his dining-room in the twilight, the door of the room being a little open. He saw distinctly a female figure enter, wrapped in a mantle, and the face concealed by a large black bonnet. She seemed to advance a few steps towards him and then stop. He had a full conviction that the figure was an illusion of vision, and amused himself for some time by watching it; at the same time observing that he could see through the figure, so as to perceive the lock of the door and other objects behind it. At length, when he moved his body a little forward, it disappeared. The appearances in these two cases were entirely visual illusions, and probably consisted of the renewal of real scenes or figures, in a manner somewhat analogous to those in Dr. Ferriar's case, though the renewal took place after a longer interval. When there is any degree of hallucination of mind, so that the phantasm is be

lieved to have a real existence, the affection is entirely of a different nature, as will be more particularly mentioned under another part of our subject.

False perceptions may be corrected by one of three methods;-by the exercise of other senses-by a comparison with the perceptions of other personsand by an exercise of judgment. If I suspect that my eye deceives me, I apply the hand, with the perfect conviction of the improbability that the two senses should be deceived at once. If this cannot be done, I appeal to the impressions of some other persons, with an equally strong conviction that the same sense will not be deceived in the same man

ner in several persons at once. Or I may do it in another way, by a reference to some known and fixed object. Suppose, for example, I see two objects where I imagine there should be but one, and suspect a visual deception; I turn my eyes to some object which I know to be single-such as the sun. If I see the sun double I know that there is a delusion of vision; if I see the sun single, I conclude the original perception to be correct. These processes imply a certain exercise of judgment; and there are other cases in which the same conviction may arise from an exercise of judgment, without any process of this kind. In one of the cases now referred to, for example, the correction took place instantly, from observing that the lock of the door was seen as if through the figure.

SECTION II.

OF CONSCIOUSNESS AND REFLECTION.

CONSCIOUSNESS appears to mean, simply, the act of attending to what is passing in the mind at the time. That more extensive operation to which we

ought to give the name of reflection, as distinguished from simple consciousness, seems to be connected with a power of remembering past perceptions and past mental processes,-of comparing them with present feelings, so as to trace between them a relation, as belonging to the same sentient being,-and, further, of tracing the laws by which the mental processes themselves are regulated. It is employed also in tracing the relations and sequences of external things, and thus proves the source of certain notions expressive of these relations. It is therefore a compound operation of mind, including various mental processes, especially consciousness, memory, and the act of comparison or judgment. The knowledge which we derive from this source, whether we call it consciousness or reflection, is referable to three heads.

I. A knowledge of the mental processes, and the laws and relations by which they are regulated; a knowledge, for example, of the laws and facts relating to memory, conception, imagination, and judgment. These will be more particularly referred to in a subsequent part of our inquiry. In the same manner we acquire our knowledge of those which have been called the active and moral powers, as love, hope, fear, joy, gratitude, &c.

II. Certain notions arising out of the exercise of the mental processes, in reference to the successio s and relations of things; our notion, for example, of time, arising out of memory and consciousness,our notion of cause-of motion-number-duration -extension or space. From simple perception we seem to acquire a knowledge of external things as existing only at the moment; and from simple consciousness a knowledge of a mental impression as existing only at the moment. Our notions of the succession of things, as implying time and motion,

require the exercise of consciousness and memory; and our notions of cause, and the various other relations of things to each other, require both memory and comparison. To the same head, in reference to another department of these faculties, belong our notions of truth and falsehood-right and wrong. These result from a certain exercise of mind, aided by that remarkable principle in our constitution which commonly receives the name of conscience.

III. With this exercise of the mental functions there spring up in the mind certain convictions, or intuitive and instinctive principles of belief. They are the immediate result of a certain exercise of the understanding, but are not referable to any process of induction or chain of reasoning, and can be considered only as an original and fundamental part of our constitution. This is a subject of great and extensive importance, and the articles of belief which are referable to it are chiefly the following:

(1.) A conviction of our own existence as sentient and thinking beings, and of mind as something distinct from the functions of the body.

(2.) A confidence in the evidence of our senses in regard to the existence and properties of external things; or a conviction that they have a real existence independent of our sensations..

(3.) A confidence in our own mental processes— that facts, for example, which are suggested to us by our memory, really occurred.

(4.) A belief in our personal identity, derived from the combined operation of consciousness and memory; or a remembrance of past mental feelings and a comparison of them with present mental feelings, as belonging to the same sentient being.

(5.) A conviction that every event must have a cause, and a cause adequate to the effect.

(6.) A confidence in the uniformity of the operations of nature; or that the same cause, acting in the