*

Kinglake's case, this gas had the peculiar effect of reviving rheumatic pains in the shoulder and kneejoints, which had not previously been felt for many months. Another gentleman, Mr James Thomson, speaks to nearly a similar fact. "I was surprised," he remarks," to find myself affected, a few minutes afterwards, with the recurrence of a pain in my back and knees, which I had experienced the preceding day from fatigue in walking. I was rather inclined to deem this an accidental coincidence than an effect of the air; but the same thing constantly occurring whenever I breathed the air, shortly after suffering pain, either from fatigue or any other accidental cause, left no doubt on my mind as to the accuracy of the observation."+

From the facts thus advanced, we need not be surprised that the impression of muscular resistance or of blows should be occasionally blended with the in cidents of ghost-stories. "After having dropped asleep," says a writer in Nicholson's Journal on Phantasms produced by Disease," an animal seemed to jump on my back with the most shrill and piercing screams, which were too intolerable for the continu ance of sleep." I have quoted a case of delirium tremens, where a man is said to have suffered even bodily pain from the severe lashing of an imaginary waggoner. In Wanley's Wonders of the Little World, I find a story, taken from Rosse's Arcana, to the following purport :-" There was an apparition

* Davy's Researches concerning Nitrous Oxide, p. 504.
+ Ibid, 515.

(saith Mr Rosse) to Mr Nicholas Smith, my dear friend, immediately before he fell sick of that fever that killed him. Having been late abroad in London, as he was going up the stairs into his chamber, he was embraced (as he thought) by a woman all in white, at which he cried out; nothing appearing, he presently sickeneth, goeth to bed, and within a week or ten days died." Beaumont also remarks of the spirits which he saw," I have been sitting by the fire with others. I have seen several spirits, and pointed to the place where they were, telling the company they were there. And one spirit whom I heard calling to me, as he stood behind me, on a sudden clapped his finger to my side, which I sensibly perceived, and started at it; and as I saw one spirit come in at the door, which I did not like, I suddenly laid hold of a pair of tongs, and struck at him with all my force, whereupon he vanished."

But it is useless to multiply stories of this kind, at the hazard of stumbling upon narratives mixed up with mere fable; otherwise I might recount, how the familiar of one man struck him on the right or left ear as he did well or ill,-how to another individual an angel came with a similar purport,

"And whipp'd the offending Adam out of him;"

how a third visionary fancied he was scourged on a bed of steel by devils,-how a lad was killed by a spirit from a box on the ear,—and, in short, how numerous other phantasms have not been content with a bodiless form, but have occasionally put on, what the pneumatologists of the middle ages were wont to

name, caro non adamica; and, under this garb, have demonstrated the miraculous force of their muscular exertions:

"I've heard a spirit's force is wonderful;

At whose approach, when starting from his dungeon,
The earth does shake, and the old ocean groans,
Rocks are removed, and towers are thunder'd down;
And walls of brass and gates of adamant

Are passable as air, and fleet like winds."

In the next place, the retina may be shewn, when subjected to strong excitements, to be no less the organ of ideas than of sensations. This fact is illustrated in the following anecdote related by Nicolai :— "A person of a sound and unprejudiced mind, though not a man of letters, whom I know well, and whose word may be credited, related to me the following case:- "As he was recovering from a violent nervous fever, being still very weak, he lay one night in bed, perfectly conscious that he was awake, when the door seemed to open, and the figure of a woman entered, who advanced to his bed-side. He looked at it for some moments, but as the sight was disagreeable, he turned himself and awakened his wife; on turning again, however, the figure was gone."* Now, in this incident, the real sensation of a closed door, to which the axis of vision had been previously directed, was followed by the fantastical representation of a door being opened by a female figure. The question then

* Tragedy of Edipus, by Lee and Dryden.
+ Nicholson's Journal, vol. vi. p. 174.

is, if those very points of the retina on which the picture of the real door had been impressed, formed the same part of the visual organ on which the idea or past feeling that constituted the phantasm was subsequently induced:-or, in other words, did the revival of the fantastic figure really affect those points of the retina which had been previously impressed by the image of the actual object? Certainly there are grounds for the suspicion, that when ideas of vision are vivified to the height of sensations, a corresponding affection of the optic nerves accompanies the illusion. A person, for instance, labouring under spectral impressions, sees the form of an acquaintance standing before him in his chamber. Every effect in this case is produced, which we might expect from the figure being impressed on the retina. The rays

of light issuing from that part of the wall which the phantasm seems to obscure, are virtually intercepted. But if impressions of vision are really renewable on the retina, their delineation ought to be always remarkable for accuracy. The author of a paper on the phantasms produced by disease, (inserted in Nicholson's Journal), remarks, that the phantastical representations of some books or parchments, exhibited either manuscript or printed characters, agreeably to the particular subject of his previous thoughts.

But the question, which I have been thus disposed to answer in the affirmative, has, since the publication of the first edition of this work, met with a most remarkable confirmation from one of the most eminent philosophers of the present day. Dr Brewster, in some remarks which he has published of his own ex

perience in these mental impressions, informs us, that, "when the eye is not exposed to the impressions of external objects, or when it is insensible to these impressions, in consequence of the mind being engrossed with its own operations, any object of mental contemplation which has either been called up by the memory, or created by the imagination, will be seen as distinctly as if it had been formed from the vision of a real object. In examining these mental impressions," he adds, "I have found that they follow the motions of the eyeball exactly like the spectral impressions of luminous objects, and that they resemble them also in their apparent immobility when the eyeball is displaced by an external force. If this result (which I state with much diffidence, from having only my own experience in its favour) shall be found generally true by others, it will follow that the objects of mental contemplation may be seen as distinctly as external objects, and will occupy the same local position in the axis of vision, as if they had been formed by the agency of light.* Hence all the phenomena of apparitions may depend upon the relative intensities of these two classes of impressions, and upon their manner of accidental combination. In perfect health, when the mind possesses a control over its powers, the impressions of external objects alone occupy the atten

* Dr Brewster, in a note subjoined to his paper, has honoured me by observing, that these results, and several others that he intends to explain in another paper, (which, I understand, will be published in the 5th Number of the Edinburgh Journal of Science,) confirm, in a remarkable manner, the views that have been given in this work.