The case of Nicolai has unquestionably been that of many whose love of science has not been able to overcome their natural reluctance to communicate to the public the particulars attending the visitation of a disease so peculiar. That such illnesses have been experienced, and have ended fatally, there can be no doubt; though it is by no means to be inferred, that the symptom of importance to our present discussion has, on all occasions, been produced from the same identical cause.

Dr. Hibbert, who has most ingeniously, as well as philosophically, handled this subject, has treated it also in a medical point of view, with science to which we make no pretence, and a precision of detail to which our superficial investigation affords us no room for extending ourselves.

The visitation of spectral phenomena is described by this learned gentleman as incidental to sundry complaints ; and he mentions, in particular, that the symptom occurs not only in plethora, as in the case of the learned Prussian we have just mentioned, but is a frequent hectic symptom—often an associate of febrile and inflammatory disorders—frequently accompanying inflammation of the brain—a concomitant also of highly excited nervous irritability—equally connected with hypochondria—and finally, united in some cases with gout, and in others with the effects of excitation produced by several gases. In all these cases there seems to be a morbid degree of sensibility, with which this symptom is ready to ally itself, and which, though inaccurate as a medical definition, may be held sufficiently descriptive of one character of the various kinds of disorder with which this painful symptom may be found allied.

A very singular and interesting illustration of such combinations as Dr. Hibbert has recorded of the spectral illusion with an actual disorder, and that of a dangerous kind, was frequently related in society by the late learned and accomplished Dr. Gregory of Edinburgh, and sometimes, I believe, quoted by him in his lectures. The narrative, to the author's best recollection, was as follows :--A patient of Dr.

Gregory, a person, it is understood, of some rank, having requested the Doctor's advice, made the following extraordinary statement of his complaint. "I am in the habit," he said, " of dining at five, and exactly as the hour of six arrives, I am subjected to the following painful visitation. The door of the room, even when I have been weak enough to bolt it, which I have sometimes done, flies wide open ; an old hag, like one of those who haunted the heath of Forres, enters with a frowning and incensed countenance, comes straight up to me with every demonstration of spite and indignation which could characterise her who haunted the merchant Abudah in the Oriental tale ; she rushes upon me ; says something, but so hastily that I cannot discover the purport, and then strikes me a severe blow with her staff. I fall from my chair in a swoon, which is of longer or shorter endurance. To the recurrence of this apparition I am daily subjected. And such is my new and singular complaint." The doctor immediately asked, whether his patient had invited any one to sit with him when he expected such a visitation ? He was answered in the negative. The nature of the complaint, he said, was so singular, it was so likely to be imputed to fancy, or even to mental derangement, that he had shrunk from communicating the circumstance to any one. " Then," said the doctor, " with your permission I will dine with you to-day, tete-a-tete, and we will see if your malignant old woman will venture to join our company." The patient accepted the proposal with hope and gratitude, for he had expected ridicule rather than sympathy. They met at dinner, and Dr. Gregory, who suspected some nervous disorder, exerted his powers of conversation, well known to be of the most varied and brilliant character, to keep the attention of his host engaged, and prevent him from thinking on the approach of the fated hour, to which he was accustomed to look forward with so much terror. He succeeded in his purpose better than he had hoped. The hour of six came almost unnoticed, and it was hoped, might pass away without any evil consequence; but it was scarce a moment struck, when the owner of the house exclaimed, in an alarmed voice:—" The hag comes again!" and dropped back in his chair in a swoon, in the way he had himself described. The physician caused him to be let blood, and satisfied himself that the periodical shocks of which his patient complained, arose from a tendency to apoplexy.

The phantom with the crutch was only a species of machinery, such as that with which fancy is found to supply the disorder called Ephialtes, or nightmare, or indeed any other external impression upon our organs in sleep, which the patient's morbid imagination may introduce into the dream preceding the swoon. In the nightmare an oppression and suffocation is felt, and our fancy instantly conjures up a spectre to lie on our bosom. In like manner it may be remarked, that any sudden noise which the slumberer hears, without being actually awakened by it—any casual touch of his person occurring in the same manner—becomes instantly adopted in his dream, and accommodated to the tenor of the current train of thought, whatever that may happen to be ; and nothing is more remarkable than the rapidity with which imagination supplies a complete explanation of the interruption, according to the previous train of ideas expressed in the dream, even when scarce a moment of time is allowed for that purpose. In dreaming, for example, of a duel, the external sound becomes, in the twinkling of an eye, the discharge of the combatants' pistols;—is an orator haranguing in his sleep, the sound becomes the applause of his supposed audience;—is the dreamer wandering among supposed ruins, the noise is that of the fall of some part of the mass. In short, an explanatory system is adopted during sleep with such extreme rapidity, that supposing the intruding alarm to have been the first call of some person to awaken the slumberer, the explanation, though requiring some process of argument or deduction, is usually formed and perfect before the second effort of the speaker has restored the dreamer to the waking world and its realities. So rapid and intuitive is the succession of ideas in sleep, as to remind us of the vision of the prophet Mahommed, in which he saw the whole wonders of heaven and hell, though the jar of water which fell when his ecstacy commenced, had not spilled its contents when he returned to ordinary existence.