lusions are always dispelled by light, a philosophical writer, whose lively phantasms were occasioned by symptomatic fever, has given the result of his own experience. "It was in my recollection," he remarks, "that Hartley, in his work upon man, adopts a theory, that the visions of fever are common ideas of the memory, recalled in a system so irritated, that they act nearly with the same force as the objects of immediate sensation, for which they are mistaken; and therefore it is,' says he, that when delirium first begins, if in the dark, the effect may be suspended by bringing in a candle, which, by illumination, gives the due preponderance to the objects of sense.' This, however, I saw was manifestly unfounded."

But it is now proper to advert more particularly to the very curious circumstance, that when Nicolai's disorder was at its greatest height, the figure of a deceased person which he saw should remain unchanged during both the shutting and the opening of the eyelids. This fact would indicate, that his ideas of vision, thus unduly vivified, exceeded in their degree of intensity those of actual impressions; for which reason they could not be annihilated by the operation of common sensible objects. One character, then, of the third stage of mental excitement is, that the illusions which are incidental to it are not dispelled by light, but may remain during the operation of sensations of an ordinary degree of intensity.

It must be admitted, however, that the persistence of phantasms is less durable when such sensible ob

# Nicholson's Journal, vol. xv. p. 292.

jects are opposed to the organ of vision as are calculated by their vivifying influence to divert the attention of the individual from the particular subject of his spectral impressions. "When my attention," observes a philosophical seer," was strongly fixed on the idea of an absent place or thing, the objects of sensation and of delirium were less perceived or regarded. When the mind was left in a passive or indolent state, the objects of delirium were most vivid, and the objects of sensation, or real objects in the room, could not be seen. But when, by a sort of exertion, the attention was roused, the phantasms became as it were transparent, and the objects of sensation were seen as if through them. There was not the least difficulty in rendering either object visible at pleasure, for the phantasms would nearly disappear while the attention was steadily fixed on the real objects."*

The transparency of these phantasms was evidently owing to their ceasing in part to affect the sensibility of the seat of vision, and to those points of the retina which were impressed by vivid objects actually present, being mingled with the dim and fading images that had been renovated.

Many of the phantasms which Nicolai saw ceased to haunt him during the influence of such pleasurable and vivifying objects as were connected with social intercourse; for he remarks, that, when he was at any other person's house, the phantasms with which he was beset were less frequent, and when he walked the public street they very seldom appeared.

*Nicholson's Journal, vol. xv. p. 292.

I may lastly observe, that when any sensible object, calculated by its casual and vivifying influence to arrest the attention of a seer, has been opposed to that part of the retina which was the object of a spectral illusion, an apparent interception of the phantasm has indicated that its persistence has been overcome; or, in other words, that the intensely vivid idea, of which the apparition consisted, had faded away, and had been succeeded by an actual impression. Thus, when the axis of vision has been directed to some particular part of a room where a phantasm was conceived to be present, and when between the eye and the phantasm some luminous object has afterwards been placed, so that rays reflected from it might impinge on the same points of the retina which were affected by the spectre, the consequence has been, that, like the phenomena of intercepted sensible impressions, actual rays of light have succeeded in effacing feelings which were ideal. This fact was proved in the case of an inhabitant of the Scottish metropolis. He was constantly annoyed by a spectral page, dressed like one of the Lord Commissioner's lacqueys, whom he always saw following close to his heels, whatever might be the occupation in which he was engaged. But to this attendant soon succeeded another no less unremitting, but far more unwelcome retainer, in the form of a frightful skeleton. An eminent medical practitioner of Edinburgh was the exorcist properly called in, who, in the course of his interrogatories, inquired, if at that very moment his patient saw the spectre? The man immediately

pointed to a particular corner of the room where he alleged his familiar was keeping guard. To this spot, therefore, the learned gentleman walked."Now, do you see the skeleton ?" he asked. "How can I," was the reply, "when you are interposed between us?" Here, then, was a satisfactory indication, not only that the retina had been actually impressed by the imaginary phantasm, but that the real object at present engaging the attention of the seer had overcome the persistence of the apparition. Soon, however, Fancy began her work again; for, with a sudden tone of exclamation that even inspired the philosopher himself with momentary alarm, the man suddenly exclaimed,-" Ay, now I see the skeleton again, for at this very moment he is peeping at me from behind your shoulders!"

But frequently, phantasms which appear without any assignable reason as arbitrarily vanish. Thus, it is recorded of one of the presidents of the Swiss cantons, that "he had occasion to visit the library of the establishment. Entering it about two o'clock in the afternoon, what was his amazement to see the former president of the same body, his deceased friend, sitting in solemn conclave in the president's chair, with a numerous list of great men, dead,' assisting him in his deliberations! He hastened from the place in fear, and went to some of his brethren in office to advise upon the most speedy measures to divorce the usurpers of their stations; but on returning with a re-enforcement of trembling associates, he found the long table in statu quo, the chairs empty, and every

mark of the mysterious deliberators vanished into

»*

air."

These remarks conclude what I have to say on the subject of the present chapter. It would appear, that when ideas of vision are rendered unduly intense, three stages of excitement may give rise to spectral impressions.

In the first stage of excitement, nothing more than the outlines of the recollected images of the mind are rendered as vivid as external impressions.

In the second stage, ideas are vivified during darkness so as to produce phantasms of a perfect form; but these are easily expelled by a strong exposure to light.

In the third stage of excitement, the illusions incidental to it are not dispelled by light, but may subsist during the influence of sensations of an ordinary degree of intensity.

This story I have quoted from a late work, the Edinburgh Literary Gazette. It is the report of an anecdote related by Sir Walter Scott, on the occasion when I read a paper to the Royal Society, which has given rise to the present expanded dissertation.