Na state of ignorance persons are liable to numerous impositions; they are easily imposed on by rumours and reports which they have not the power of investigating, and still more easily imposed on by their own impressions or notions. Of all the impositions which have vexed the ignorant, a belief in the reality of spectral appearances has been one of the most ridiculous, yet one of the longest and most zealously supported. This belief was once current even among men reputed for their learning-that is, a kind of learning, not founded on a correct knowledge of nature-but, by the progress of inquiry, it has gradually been abandoned by persons of education, and now is maintained only by those whose minds have not been instructed on the subject. Considering that this belief, like every other error, is injurious to happiness, and that, in a particular manner, the young require to be put on their guard against it, we propose, in the present paper, to explain the theory of spectral illusions-how they originate in the mind, and are in no respect supernatural in their character.

To obtain right ideas of this curious, and, to many, mysterious subject, it is necessary to understand, in the first place, what kind of a thing the human mind is, and how it operates in connection with the senses, or at least two of them-seeing and hearing. The seat of the mind is in the brain; in other words, the brain is the organ or mass of organs by which the thinking faculties act. Like

an instrument finely tuned, the brain, when in a sound state of health, performs its part in our economy with fidelity. Shut up in the skull, however, it has no communication with external nature except through the medium of the senses. The senses are the channels of intelligence to the brain. When the eye receives the impression or picture of a thing presented to it, that impression is carried by a nerve to the brain, where the consciousness or mind recognises it; and the same thing occurs with the ear in the transmission of sound. The ordinary notion, therefore, that the eye sees, is scarcely correct. It is the mind, through the operation of the brain, the optic nerve, and the eye, which sees. The eye is only an instrument of vision and recognition. Such is the ordinary process of seeing, and of having a consciousness of what is presented to the eye; and we perceive that the outer organ of vision performs but an inferior part in the operation. There is, indeed, a consciousness of seeing objects, without using the eyes. With these organs shut, we can exert our imagination so far as to recall the image of objects which we formerly have seen. Thus, when in an imperfect state of sleep, with the imagination less or more active, we think that we see objects, and mingle in strange scenes; and this is called dreaming. Dreams, therefore, arise principally from a condition of partial wakefulness, in which the unregulated imagination leads to all kinds of visionary conceptions. In a state of entire wakefulness, and with the eyes open, unreal conceptions of objects seemingly present may also be formed; but this occurs only when the system is disordered by disease.

We are now brought to an understanding of the cause of those illusions which, under the name of ghosts, apparitions, or spectres, have in all ages disturbed the minds of the credulous. The disorder which leads to the formation of these baseless visions may be organic or functional, or a combination of both. Organic disorder of the body is that condition in which one or more organs are altered in structure by disease. Functional disorder is less serious in character: it is that condition of things where the healthy action of the organ or organs, in part or whole, is impeded, without the existence of any disease of structure. Lunacy, if not arising from organic disorder, hovers between it and functional derangement, in either case producing unreal conceptions in the mind. Functional disorder may arise in various ways, and be of different kinds. It may be said that violent excitement of the imagination or passions constitutes functional mental disorder: 'Anger is a short madness,' said the Romans wisely. As for functional bodily disorder, temporary affections of the digestive organs may be pointed to as common causes of such cases of physical derangement. All these disorders, and kinds of disorders, may appear in a complicated form; and, what is of most importance to our present argument, the nervous system, on which depend the action of the senses, the

powers of the will, and the operation of all the involuntary functions (such as the circulation of the blood, and digestion), is, and must necessarily be, involved more or less deeply in all cases of constitutional disorder, organic or functional. These powers of the nerves, which form, as we have seen, the sole medium by which mind and body act and react on each other, are clearly, then, connected with the production of every kind of illusory impression.

In lunacy, from organic derangement, these impressions are usually the most vivid. Every lunatic tells you he sees spectres, or unreal persons; and no doubt they are seemingly present to his diseased perceptions. The same cause, simple insanity, partial or otherwise, and existing either with or without structural brain disease, has been, we truly believe, at the foundation of many more apparitioncases than any other cause. By far the greatest number of such cases ever put on record, have been connected with fanaticism in religious matters; and can there be a doubt that the majority of the poor creatures, men and women, who habitually subjected themselves, in the early centuries of the church, to macerations and lacerations, and saw signs and visions, were simply persons of partially deranged intellect? St Theresa, who lay entranced for whole days, and who, in the fervour of devotion, imagined that she was frequently addressed by the voice of God, and that St Peter and St Paul would often in person visit her solitude, is an example of this order of monomaniacs. That this individual, and others like her, should have been perfectly sensible on all other points, is a phenomenon in the pathology of mind too common to cause any wonder. We would ascribe, we repeat, a large class of apparition-cases, including these devotional ones, to simple mental derangement. The eye in such instances may take in a correct impression of external objects, but this is not all that is wanting. A correct perception by the mind is essential to healthy and natural vision, and this perception the deranged intellect cannot effect.

We should go further than this for a complete elucidation of spectral illusions. At the time the spectre makes its appearance, the mind may be neither altogether diseased nor altogether healthful; the perceptive powers may recognise through the eye all surrounding objects exactly as they appear, but, almost in the same instant of time, the mind may mix up an unreal object with them. How, then, is the unreal object introduced into the scene? There is the strongest ground for believing that the unreal object-the spectre is an idea of the mind acting on the optic nerve, and impressing a picture on the retina, just as effectually as if the object were external to the person. The mind, as it were, daguerreotypes the idea-the flash of thought-on the retina, or mirror of the eye, where it is recognised by the powers of perception. That spectres are mental pictures, is forcibly stated as follows by Sir David Brewster: 'I propose to shew that the "mind's eye" is actually the

'body's eye, and that the retina is the common tablet on which both classes of impressions are painted, and by means of which they receive their visual existence according to the same optical laws. Nor is this true merely in the case of spectral illusions. It holds good of all ideas recalled by the memory, or created by the imagination, and may be regarded as a fundamental law in the science of pneumatology.

In the healthy state of the mind and body, the relative intensity of these two classes of impressions on the retina are nicely adjusted. "The mental pictures are transient, and comparatively feeble, and in ordinary temperaments are never capable of disturbing or effacing the direct images of visible objects. The affairs of life could not be carried on if the memory were to intrude bright representations of the past into the domestic scene, or scatter them over the external landscape. The two opposite impressions, indeed, could not coexist. The same nervous fibre which is carrying from the brain to the retina the figures of memory, could not at the same instant be carrying back the impressions of external objects from the retina to the brain. The mind cannot perform two different functions at the same instant, and the direction of its attention to one of the two classes of impressions necessarily produces the extinction of the other. But so rapid is the exercise of mental power, that the alternate appearance and disappearance of the two contending impressions is no more recognised than the successive observations of external objects during the twinkling of the eyelids.'*

With these general observations, we proceed to an analysis of the different kinds of spectre-seeing, beginning with a short explanation of dreaming and somnambulism, with which apparitional illusions are intimately associated.

DREAMS-SOMNAMBULISM.

Dreaming is a modification of disordered mental action, arising usually from some kind of functional derangement. In sound sleep, the functions of digestion, the circulation of the blood, and all others, may be said to be duly in action, and the mind is accordingly not disturbed. If, however, any of the bodily functions be in a state of derangement; if, in particular, the digestion be incommoded, which it ordinarily is in an artificial mode of life, the senses, the nerves, the mind, will also be probably affected, and an imperfect sleep, with an imperfect consciousness, is the result. According to the best writers on the subject, it has been ascertained that, in beginning to sleep, the senses do not unitedly fall into a state of slumber, but drop off one after the other. The sight ceases, in consequence of the protection of the eyelids, to receive impressions first, while all

* Letters on Natural Magic.

the other senses preserve their sensibility entire. The sense of taste is the next which loses its susceptibility of impressions, and then the sense of smelling. The hearing is next in order; and, last of all, comes the sense of touch. Furthermore, the senses are thought to sleep with different degrees of profoundness. The sense of touch sleeps the most lightly, and is the most easily awakened; the next easiest is the hearing; the next is the sight; and the taste and smelling awake the last. Another remarkable circumstance deserves notice; certain muscles and parts of the body begin to sleep before others. Sleep commences at the extremities, beginning with the feet and legs, and creeping towards the centre of nervous action. The necessity for keeping the feet warm and perfectly still, as a preliminary of sleep, is well known. From these explanations, it will not appear surprising that, with one or more of the senses, and perhaps also one or more parts of the body imperfectly asleep, there should be at the same time an imperfect kind of mental action, which produces the phenomenon of dreaming.

A dream, then, is an imperfectly formed thought. Much of the imperfection and incoherency of such thoughts is from having no immediate consciousness of surrounding objects. The imagination revels unchecked by actual circumstances, and is not under the control of the will. Ungoverned by any ordinary standards of reason, we, in dreaming, have the impression that the ideas which chase each other through the mind are actual occurrences: a mere ill-formed thought is imagined to be an action. As thought is very rapid, it thus happens that events which would take whole days or a longer time in performance, are dreamed in a few moments. So wonderful is this compression of a multitude of transactions into the very shortest period, that when we are accidentally 'awakened from a profound slumber by a loud knock at, or by the rapid opening of, the door, a train of actions which it would take hours, or days, or even weeks to accomplish, sometimes passes through the mind. Time, in fact, seems to be in a great measure annihilated. An extensive period is reduced, as it were, to a single point, or rather a single point is made to embrace an extensive period. In one instant we pass through many adventures, see many strange sights, and hear many strange sounds. If we are awaked by a loud knock, we have perhaps the idea of a tumult passing before us, and know all the characters engaged in it-their aspects, and even their very names. If the door open violently, the flood-gates of a canal may appear to be expanding, and we may see the individuals employed in the process, and hear their conversation, which may seem an hour in length; if a light be brought into the room, the notion of the house being in flames invades us, and we are witnesses to the whole conflagration from its commencement till it be finally extinguished. The thoughts which arise in such situations are endless, and assume an infinite variety of aspects.