The projected analysis has been crowned with success. The fumes of superstition have been driven off, and the ghosts have been reduced to rational elements. All trace of supernatural agency has vanished; and in its place are found three principles—one physical, two psychical—by the help of which every conceivable ghost may in future be alternately decomposed and recompounded by the merest tyro.

The first of which I shall describe the nature and operation is a psychical truth, already known to most persons of education. It is of very general use in ghost-building; it forms the immediate personnel of every ghost; and is of so active a nature that alone, or assisted by a little credulity, it is enough to constitute the simplest kind—a common fetch. Mixed with a dose of mental anxiety, or as much remorse as will lie on the point of a dagger, it will form a troublesome retrospective ghost. The second principle—a physical one, less generally known—is the basis of that sturdy apparition the churchyard ghost, which it will turn out in very fair style aided by fancy alone; but, to perfect the illusive result, the co-operation of the first principle is necessary. The third, an entirely new one, is the foundation of real ghosts—that is, of ghosts which announce unexpected events, distant in space or time; the same principle is concerned in true dreams, and in second-sight.

The first of the three principles adverted to is the physiological fact that, when the blood is heated, the nervous system overstrained, or digestion out of sorts, the thereby directly or sympathetically disordered brain is liable to project before us illusory forms, which are coloured and move like life, and are so far undistinguishable from reality. Sometimes a second sense is drawn into the phantasmagoria, and the fictitious beings speak as you do. Almost always the illusion stops there. But in one or two marvellous cases, the touch has been involved in the hallucination, and the ghost has been tangible. These phenomena are termed sensorial illusions. The visual part of them, the first and commonest, has been the most attended to. The cause immediately producing it appears to be an affection, not of the organ of vision, but of that part of the brain in which the nerves of seeing take their origin. This organ it is which in health realizes our sensations of colour, and converts them into visual perceptions. Like other parts of the brain, it is stored with memories of its past impressions, ready to be evoked—either pure and true by conception, or any how combined by fancy. In perfect health, a chance moment of warm recollection will call up from this source the once familiar face transiently, but how distinctly!

In its morbid state, the beings it projects before us are for the most part strangers, just as the personages we meet in our dreams are exceptionally only our living and present acquaintance.

The most instructive case of sensorial illusions on record, as containing the largest illustration of the phenomena, is that of Nicolai, the bookseller of Berlin. The narrative was read before the Academy of Sciences at Berlin, in 1799. Its substance runs thus:—Nicolai had met with some family troubles, which much disturbed him. Then, on the first of January, 1791, there stood before him, at the distance of ten paces, the ghost of his eldest son. He pointed at it, directing his wife to look. She saw it not, and tried to convince Nicolai that it was an illusion. In a quarter of an hour it vanished. In the afternoon, at four o’clock, it came again. Nicolai was alone. He went to his wife’s room, the ghost followed him. About six other apparitions joined the first, and they walked about among each other. After some days the apparition of his son stayed away; but its place was filled with the figures of a number of persons, some known, some unknown to Nicolai—some of dead, others of living persons. The known ones represented distant acquaintances only. The figures of none of Nicolai’s habitual friends were there. The appearances were almost always human; occasionally a man on horseback, and birds, and dogs, would present themselves. The apparitions came mostly after dinner, at the commencement of digestion; they were just like real persons, the colouring a thought fainter. The apparitions were equally distinct whether Nicolai was alone or in society, in the dark as by day; in his own house or in those of others; but in the latter case they were less frequent, and they very seldom made their appearance in the streets. During the first eight days they seemed to take very little notice of one another, but walked about like people at a fair, only here and there communing with each other. They took no notice of Nicolai, or of the remarks he addressed regarding them to his wife and physician. No effort of his would dismiss them, or bring an absent one back. When he shut his eyes, they sometimes disappeared, sometimes remained; when he opened his eyes, they were there as before. After a week they became more numerous, and began to converse. They conversed with one another first, and then addressed him. Their remarks were short and unconnected, but sensible and civil. His acquaintances inquired after his health, and expressed sympathy with him, and spoke in terms comforting him. The apparitions were most conversable when he was alone; nevertheless, they mingled in the conversation when others were by, and their voices had the same sound as those of real persons. The illusion went on thus from the 24th of February to the 20th of April; so that Nicolai, who was in good bodily health, had time to become tranquillized about the nature of his visiters, and to observe them at his ease. At last they rather amused him; then the doctors thought of an efficient plan of treatment. They prescribed leeches; and then followed the “denouement” of this interesting representation. The apparitions became pale, and vanished. On the 20th of April, at the time of applying the leeches, Nicolai’s room was full of figures moving about among each other. They first began to have a less lively motion; shortly afterwards their colours became paler, in another half hour paler still, though the forms still remained. About seven o’clock in the evening the figures had become colourless, and they moved scarcely at all; but their outline was still tolerably perfect. Gradually that became less and less defined; at last they disappeared, breaking into air, fragments only remaining, which at last all vanished. By eight o’clock all were gone, and Nicolai subsequently saw no more of them.

In general, as in Nicolai’s case, the sight is the sense at first and alone affected. Illusions of the hearing, if they occur, follow later. In some most extraordinary cases, I have observed that the touch has likewise participated in the affection; the following is an instance:—

Herr von Baczko, already subject to visual hallucinations of a diseased nervous system, his right side weak with palsy, his right eye blind, and the vision of the left imperfect, was engaged one evening shortly after the battle of Jena, as he tells in his autobiography, in translating a pamphlet into Polish, when he felt a poke in his loins. He looked round, and found that it proceeded from a Negro or Egyptian boy, seemingly about twelve years of age. Although he was persuaded the whole was an illusion, he thought it best to knock the apparition down, when he felt that it offered a sensible resistance. The Negro then attacked him on the other side, and gave his left arm a particularly disagreeable twist, when Baczko again pushed him off. The Negro continued to visit him constantly during four months, preserving the same appearance, and remaining tangible; then he came seldomer; and, finally appearing as a brown-coloured apparition with an owl’s head, he took his leave.

Sensorial illusions, technically speaking, are not mental delusions; or they become so only when they are believed to be realities. So sensorial illusions are not insanity, neither do they menace that disorder: they are not its customary precursors. Nevertheless, they may accompany the first outbreak of madness; and they occur much more frequently in lunatics than in persons of sound mind. In insanity they are firmly believed in by the patient, whose delusions they may either suggest or be shaped by. In insanity, illusions of the hearing often occur alone, which is comparatively rare in sane people.

The objects of visual illusions are commonly men and women; but animals, and even inanimate objects, sometimes constitute them. A lady whose sight was failing her had long visions every day of rows of buildings, houses, and parks, and such like. The subjects of visual illusions are generally perfectly trivial, like the events of a common dream. But, though susceptible of change, their custom is to recur with much the same character daily. One patient could at will summon the apparition of an acquaintance to join the rest; but, once there, he could not get rid of him.

Sometimes it happens that sensorial illusions are in accordance with a congenial train of thought—for instance, with peculiar impressions referring to religion. They are then very liable to be construed by the patient into realities, and to materially influence his conversation and conduct. He remains, no doubt, strictly sane in the midst of these delusions. But he is apt not to be thought so; or, to use a figure, the world’s opinion of such a person becomes a polar force, and society is divided into his admiring followers and those who think him a lunatic. Such was, and remains, the fate of Schwedenborg.

Schwedenborg, the son of a Swedish clergyman of the name of Schwedberg, ennobled as Schwedenborg, was up to the year 1743, which was the fifty-fourth of his age, an ordinary man of the world, distinguished only in literature, having written many volumes on philosophy and science, and being professor in the Mineralogical School, where he was much respected. On a sudden, in the year 1743, he believed himself to have got into a commerce with the world of spirits, which so fully took possession of his thoughts, that he not only published their revelations, but was in the habit of detailing their daily chat with him. Thus he says, “I had a conversation the other day on that very point with the apostle Paul,” or with Luther, or some other dead person. Schwedenborg continued in what he believed to be constant communion with spirits till his death, in 1772. He was, without doubt, in the fullest degree convinced of the reality of his spiritual commerce. So in a letter to the Wurtemburg Prelate, Oetinger, dated November 11, 1766, he uses the following words: “If I have spoken with the apostles? To this I answer, I conversed with St. Paul during a whole year, particularly with reference to the text, Romans iii. 28. I have three times conversed with St. John, once with Moses, and a hundred times with Luther, who allowed that it was against the warning of an angel that he professed fidem solam, and that he stood alone upon the separation from the Pope. With angels, finally, have I these twenty years conversed, and converse daily.”

Of the angels, he says, “They have human forms, the appearance of men, as I have a thousand times seen; for I have spoken with them as a man with other men—often with several together—and I have seen nothing in the least to distinguish them from other men.” They had, in fact, exactly the same appearance as Nicolai’s visiters. “Lest any one should call this an illusion, or imaginary perception, it is to be understood that I am accustomed to see them when myself perfectly wide awake, and in full exercise of my observation. The speech of an angel, or of a spirit, sounds like and as loud as that of a man; but it is not heard by the bystanders. The reason is, that the speech of an angel, or a spirit, finds entrance first into a man’s thoughts, and reaches his organs of hearing from within.” A wonderful instance this last reason how it is possible cum ratione insanire; he analyzes the illusion perfectly, even when he is most deceived by it.

“The angels who converse with men speak not in their own language, but in the language of the country; and likewise in other languages which are known to a man, not in languages which he does not understand.” Schwedenborg here interrupted the angels, and, to explain the matter, observed that they most likely appeared to speak his mother tongue, because, in fact, it was not they who spoke, but himself after their suggestions. The angels would not allow this, and went away at the close of the conversation unpersuaded.

The following fiction is very fine: “When approaching, the angels often appear like a ball of light; and they travel in companies so grouped together—they are allowed so to unite by the Lord—that they may act as one being, and share each other’s ideas and knowledge; and in this form they bound through the universe, from planet to planet.”

A still more interesting example of the influence of sensorial illusions on human conduct is furnished by the touching history of Joan of Arc.

“It is now seven years ago,” so spoke before her judges the simple but high-minded maiden—“it was a summer day, towards the middle hour, I was about thirteen years old, and was in my father’s garden, that I heard for the first time, on my right hand, towards the church, a voice, and there stood a figure in a bright radiance before my eyes. It had the appearance and look of a right good and virtuous man, bore wings, was surrounded with light on all sides, and by the angels of heaven. It was the archangel Michael. The voice seemed to me to command respect; but I was yet a child, and was frightened at the figure, and doubted very much whether it were the archangel. I saw him and the angels as distinctly before my eyes as I now see you, my judges.” With words of encouragement the archangel announced to her that God had taken pity upon France, and that she must hasten to the assistance of the King. At the same time he promised her that St. Catharine and St. Margaret would shortly visit her: he told her that she should do what they commanded her, because they were sent by God to guide and conduct her. “Upon this,” continued Joan, “St. Catharine and St. Margaret appeared to me, as the archangel had foretold. They ordered me to get ready to go to Robert de Beaudricourt, the King’s captain. He would several times refuse me, but at last would consent, and give me people who would conduct me to the King. Then should I raise the siege of Orleans. I replied to them that I was a poor child, who understood nothing about riding on horseback and making war. They said I should carry my banner with courage; God would help me, and win back for my king his entire kingdom. As soon as I knew,” continued Joan, “that I was to proceed on this errand, I avoided as much as I could taking part in the sports and amusements of my young companions.” “So have the saints conducted me during seven years, and have given me support and assistance in all my need and labours; and now at present,” said she to her judges, “no day goes by but they come to see me.” “I seldom see the saints that they are not surrounded with a halo of light; they wear rich and precious crowns, as it is reasonable they should. I see them always under the same forms, and have never found in their discourse any discrepancies. I know how to distinguish one from the other, and distinguish them as well by the sound of their voices as by their salutation. They come often without my calling upon them. But when they do not come, I pray to the Lord that he will send them to me; and never have I needed them but they have visited me.”

Such is part of the defence of the heroic Joan of Arc, who was taken prisoner by the Duke of Burgundy on the 23d of May, 1430—sold by him for a large sum to the English, and by them put on her trial as a heretic, idolatress, and magician—condemned, and finally burned alive on the 30th of May, 1431!

Her innocence, simplicity, and courage incense one sadly against her judges; but it is likely there were at that time many good and sensible persons who approved of her sentence, and never suspected its cruelty and injustice. Making allowance for the ignorance and barbarity of the age, her treatment was, perhaps, not worse than that of Abd-el-Kader now. Her visions—they were palpably the productions of her own fancy, the figures of saints and angels, which she had seen in missals, projected before her mental sight; and their cause the instinctive workings, unknown to herself, of her young high-couraged and enthusiastic heart, shaping its suggestions into holy prophesyings—the leading facts of which her resolute will realized, while their actual discrepancies with subsequent events she pardonably forgot.1

I will present yet another and less pleasing picture, where the subject of sensorial illusions was of infirm mind, and they struck upon the insane chord, and reason jangled harshly out of tune. It would be a curious question whether such a sensorial illusion as overthrew the young seer’s judgment in the following case, could have occurred to a mind previously sane; whether, for instance, it could have occurred to Schwedenborg, and, in that event, how he would have dealt with it.

Arnold (a German writer) relates, in his history of the church and of heresy, how there was a young man in KÖnigsberg, well educated, the natural son of a priest, who had the impression that he was met near a crucifix on the wayside by seven angels, who revealed to him that he was to represent God the Father on earth, to drive all evil out of the world, &c. The poor fellow, after pondering upon this illusion a long time, issued a circular, beginning thus:

“We John, Albrecht, Adelgreif, Syrdos, Amata, Kanemata, Kilkis, Mataldis, Schmalkilimundis, Sabrandis, Elioris, Hyperarch-High-priest and Emperor, Prince of Peace of the whole world, Hyperarch-King of the holy kingdom of Heaven, Judge of the living and of the dead, God and Father, in whose divinity Christ will come on the last day to judge the world, Lord of all lords, King of all kings,” &c.

He was thereupon thrown into prison at KÖnigsberg, where every means were used by the clergy to reclaim him from these blasphemous and heretical notions. To all their entreaties, however, he listened only with a smile of pity—“that they should think of reclaiming God the Father.” He was then put to the torture, and as what he endured made no alteration in his convictions, he was condemned to have his tongue torn out with red-hot tongs, to be cut in four quarters, and then burned under the gallows. He wept bitterly, not at his own fate, but that they should pronounce such a sentence on the Deity. The executioner was touched with pity, and implored him to make a final recantation. But he persisted that he was God the Father, whether they pulled his tongue out by the roots or not; and so he was executed!

From the preceding forcible illustrations of the working of sensorial illusions on individual minds, it is to descend a little in interest to trace their ministry in giving rise to the rickety forms of popular superstition. However, the material may be the same, whether it be cast for the commemoration of a striking event or coined for vulgar currency. And here is a piece of the latter description, with the recommendation of being at least fresh from the mint, and spic-and-span new—an instance of superstition surviving in England in the middle of the nineteenth century.

A young gentleman, who has recently left Oxford, told me that he was one evening at a supper-party in college, when they were joined by a common friend on his return from hunting. They expected him, but were struck with his appearance. He was pale and agitated. On questioning him, they learned the cause. During the latter part of his ride home, he had been accompanied by a horseman, who kept exact pace with him, the rider and horse being close facsimiles of himself and the steed he rode, even to the copy of a new fangled bit which he sported that day for the first time. He had, in fact, seen his “double” or “Fetch,” and it had shaken his nerves pretty considerably. His friends advised him to consult the college-tutor, who failed not to give him some good advice, and hoped the warning would not be thrown away. My informant, who thought the whole matter very serious, and was inclined to believe the unearthly visit to have been no idle one, added that it had made the ghost-seer, for the time at least, a wiser and better man.

Such a visionary duplicate of one’s-self—one’s fetch—is a not unfrequent form of sensorial illusion. In more ignorant days the appearance of a fetch excited much apprehension. It was supposed to menace death or serious calamity to its original. Properly viewed, unless it proceed from hard work and overstrained thought, (from which you can desist,) it indicates something wrong in your physical health, and its warning goes no further than to consult a doctor, to learn, “what rhubarb, senna, or what purgative drug will drive the spectre hence.” The efficiency of such means was shown in the case of Nicolai. Yet in this case, I may remark, the originating cause of the attack had been anxiety about the very son whose apparition was the first of the throng to visit him. Had the illusion continued limited to the figure of the son, it would have been more questionable what art could do towards dismissing it. At all events, in such a case, the first thing is to remove the perilous stuff that weighs upon the mind. So the personage whose words I have been using was doubtless right, in his own case, to “throw physic to the dogs.”

In the tragedy of Macbeth, sensorial illusions are made to play their part with curious physiological correctness. The mind of Macbeth is worn by the conflict between ambition and duty. At last his better resolves give way; and his excited fancy projects before him the fetch of his own dagger, which marshals him the way that he shall go. The spectator is thus artistically prepared for the further working of the same infirmity in the apparition of Banquo, which, unseen by his guests, is visible only to the conscience-stricken murderer. With a scientific precision no less admirable, the partner of his guilt—a woman—is made to have attacks of trance, (to which women are more liable than men,) caused by her disturbed mind; and in her trance the exact physiological character of one form of that disorder is portrayed—she enacts a dream, which is the essence of somnambulism.

One almost doubts whether Shakspeare was aware of the philosophic truth displayed in these master-strokes of his own art. The apparitions conjured up in the witch scenes of the same play, and the ghost in Hamlet, are moulded on the pattern of vulgar superstition. He employs indifferently the baser metal and the truthful inspirations of his own genius—realizing Shelley’s strange figure of

So they say the sun is himself dark as a planet, and his atmosphere alone the source of light, through the gaps in which his common earth is seen. I am tempted—but it would be idle, and I refrain—to quote an expression or two, or a passage, from Shakspeare, exemplifying his wonderful turn for approximating to truths of which he must have been ignorant—where lines of admired and unaccountable beauty have unexpectedly acquired lucidity and appositeness through modern science. While, to make a quaint comparison, his great contemporary, Bacon, employed the lamp of his imagination to illuminate the paths to the discovery of truth, Shakspeare would, with random intuition, seize on the undiscovered truths themselves, and use them to vivify the conceptions of his fancy.

Let me now turn to explain a ghost of a more positive description—the churchyard ghost. The ghost will perhaps exclaim against so trivial a title, and one so unjust in reference to old superstition; but it will be seen he deserves no better. In popular story he had a higher office; his duty was to watch the body over which church rites had not been performed, that had been rudely inearthed after violent death. As thus—

There was a cottage in a village I could name to which a bad report attached. More than one who had slept in it had seen, at midnight, the radiant apparition of a little child standing on the hearth-stone. At length suspicion was awakened. The hearth-stone was raised, and there were found buried beneath it the remains of an infant. A story was now divulged how the last tenant and a female of the village had abruptly quitted the neighbourhood. The ghost was real and significant enough.

But here is a still better instance from a trustworthy German work, P. Kieffer’s Archives. The narrative was communicated by Herr Ehrman of Strasburg, son-in-law of the well-known writer Pfeffel, from whom he received it.

The ghost-seer was a young candidate for orders, eighteen years of age, of the name of Billing. He was known to have very excitable nerves, had already experienced sensorial illusions, and was particularly sensitive to the presence of human remains, which made him tremble and shudder in all his limbs. Pfeffel, being blind, was accustomed to take the arm of this young man, and they walked thus together in Pfeffel’s garden, near Colmar. At one spot in the garden, Pfeffel remarked that his companion’s arm gave a sudden start, as if he had received an electric shock. Being asked what was the matter, Billing replied, “Nothing.” But on their going over the same spot again, the same effect recurred. The young man being pressed to explain the cause of his disturbance, avowed that it arose from a peculiar sensation which he always experienced when in the vicinity of human remains; that it was his impression a human body must be interred there; but that, if Pfeffel would return with him at night, he should be able to speak with greater confidence. Accordingly they went together to the garden when it was dark, and as they approached the spot, Billing observed a faint light over it. At ten paces from it he stopped, and would go no farther, for he saw hovering over it, or self-supported in the air—its feet only a few inches from the ground—a luminous female figure, nearly five feet high, with the right arm folded on her breast, the left hanging by her side. When Pfeffel himself stepped forward and placed himself about where the figure appeared to be, Billing said it was now on his right hand, now on his left, now behind, now before him. When Pfeffel cut the air with his stick, it seemed as if it went through and divided a light flame, which then united again. The visit, repeated the next night, in company with some of Pfeffel’s relatives, gave the same result. They did not see any thing. Pfeffel then, unknown to the ghost-seer, had the ground dug up, when there was found at some depth, beneath a layer of quicklime, a human body in progress of decomposition. The remains were removed, and the earth carefully replaced. Three days afterwards, Billing, from whom this whole proceeding had been kept concealed, was again led to the spot by Pfeffel. He walked over it now without experiencing any unusual impression whatever.

The explanation of this mysterious phenomenon has been but recently arrived at. The discoveries of Von Reichenbach, of which I gave a sketch in the first letter, announce the principle on which it depends. Among these discoveries is the fact that the Od force makes itself visible as a dim light or waving flame to highly sensitive subjects. Such persons, in the dark, see flames issuing from the poles of magnets and crystals. Von Reichenbach eventually discovered that the Od force is distributed universally, although in varying quantities. But among the causes which excite its evolution, one of the most active is chemical decomposition. Then, happening to remember Pfeffel’s ghost story, it occurred to Von Reichenbach that what Billing had seen was possibly Od light. To test the soundness of this conjecture, Miss Reichel, a very sensitive subject, was taken at night to an extensive burying-ground near Vienna, where interments take place daily, and there are many thousand graves. The result did not disappoint Von Reichenbach’s expectations. Whithersoever Miss Reichel turned her eyes, she saw masses of flame. This appearance manifested itself most about recent graves. About very old ones it was not visible. She described the appearance as resembling less bright flame than fiery vapour, something between fog and flame. In several instances the light extended four feet in height above the ground. When Miss Reichel placed her hand on it, it seemed to her involved in a cloud of fire. When she stood in it, it came up to her throat. She expressed no alarm, being accustomed to the appearance.

The mystery has thus been entirely solved; for it is evident that the spectral character of the luminous apparition, in the two instances which I have narrated, had been supplied by the seers themselves. So the superstition has vanished; but, as usual, it veiled a truth.