and the laws of dead matter take possession of the body. This state of countenance is thus beautifully alluded to by Byron : 7. He who hath bent him o'er the dead, Have swept the lines where beauty lingers), The rapture of repose that's there, The doom he dreads, yet dwells upon- So fair, so calm, so softly sealed, The first, last look by death revealed! So coldly sweet, so deadly fair, We start, for soul is wanting there. This is the loveliness in death That parts not quite with parting breath; A gilded halo hovering round decay, The farewell beam of feeling pass'd away! Spark of that flame, perchance of heavenly birth, 1 FUNC'-TIONS, actions or offices. 15 STOL-ID, stupid. 6 TAB'-ER-NA-CLE, a temporary habitation. LES. XVI.-DISORDERS OF THE NERVOUS SYSTEM. VISIONS, APPARITIONS, AND DREAMS, AS VIEWED IN CONNECTION WITH PHYSIOLOGY. 1. Ir has already been stated that a knowledge of external things is conveyed to the brain through the medium of the nerves of sensation. How the items of knowledge thus obtained are stored up in the brain, and how the mind is able to recall them in some subsequent period, and form of them new combinations, has usually been thought to belong especially to the department of mental philosophy to consider: but even here it will be found that anatomy and physiology furnish the safest guides to investigation. 2. The involuntary1 action of the muscles of the heart and lungs is accounted for on the supposition that, at the origin of the nerves which control them, an amount of directing nerv ous force is stored up sufficient to continue the motion, without mental control, until the supply is exhausted. It is also believed that the sensations which the nerves of taste, touch, smell, sight, and hearing convey to the brain, leave upon that organ, or stored up in its sensorium or seat of power, impressions which can be fully eradicated only by death; and that these impressions, which may be regarded as images of the outward world, the mind makes use of in memory, in imagination, in visions, in fancied apparitions, and in dreams, often forming new and strange combinations very different from the original impressions. 3. Some physiologists believe that every impression made upon the material substance of the brain produces some permanent change in its structure, and that one impression never completely effaces another; that the mind can, as it were, see all of them, and that what the mind or soul thus learns, death itself can not destroy. Even certain physical phenomena, explained by Dr. Draper, give countenance to the theory of permanent impressions upon the material substance of the brain. He says, "If on a cold, polished piece of metal, any object, as a wafer, is laid, and the metal then be breathed upon, and, when the moisture has had time to disappear, the wafer be thrown off, though now upon the polished surface the most critical inspection can discover no trace of any form, yet, if we breathe upon it, a spectral3 figure of the wafer comes into view, and this may be done again and again. 4. "Nay, even more; if the polished metal be carefully put aside where nothing can deteriorate its surface, and be so kept for many months, on breathing again upon it the shadowy form emerges; or, if a sheet of paper on which a key or other object is laid be carried for a few moments into the sunshine, and then instantaneously viewed in the dark, the key being simultaneously removed, a fading spectre of the key on the paper will be seen; and if the paper be put away where nothing can disturb it, and so kept for many months, if it then be carried into a dark place and laid on a piece of hot metal, the spectre of the key will come forth. In the case of bodies more highly phosphorescent than paper, the spectres of many different objects which may have been in succession laid originally thereupon will, on warming, emerge in their proper order. 5. "I introduce these illustrations," says Dr. Draper, "for the purpose of showing how trivial are the impressions which may be thus registered and preserved. Indeed, I believe that a shadow never falls upon a wall without leaving thereupon its permanent trace-a trace which might be made visible by resorting to proper processes. But if on such inorganic5 surfaces impressions may in this way be preserved, how much more likely is it that the same thing occurs in the purposely constituted ganglia of the brain!" But, whether the impressions of sense be permanently fixed in the material substance of the brain or not, there is no reason for supposing that any perceptions which the mind has once taken notice of can ever be lost; and if at any time memory fails to recall them, it is because the brain, and not the mind itself, has become impaired. 6. While, in the exercise of ordinary memory, perceptions and trains of thought are recalled in their real character and natural order, it is not so in what are called visions, fancied apparitions, and in dreams. The most common visions-unreal objects which we fancy-are doubtless the remains of impressions which have been made on the optic nerve, and which are recalled by a strong mental effort. Others arise from disease of the nerve, often producing, by the impressions conveyed from the diseased nerve to the brain, grotesque images among the real objects at which we are looking. Some unusual pressure of blood upon this nerve will often produce apparent flashes of light, or objects apparently floating in the air. These appearances are indications of disease in the nerve. 7. When, in addition to the optic nerve, portions of the brain become affected by disease, former impressions often become mingled with the present, and the complicated scenes of a passing drama are displayed. Thus, in the delirium tremens, which follows a cessation from the customary use of alcohol, phantoms appear moving around among real objects. "The form of a cloud no bigger than the hand may perhaps first be seen floating over the carpet; but this, as the eye follows it, takes on a sharp contours and definite shape, and the sufferer sees with dismay a moping raven on some of the more distant articles of furniture. Or, out of an indistinct cloud, faces, sometimes of surprising loveliness, but more frequently of hideous aspects, emerge, one face succeeding as another dies away. The mind, ever ready to practice imposture upon itself, will at last accompany the illusion with grotesque or even dreadful inventions." 8. The illusions to which one is subject under such derangements of the brain take a character from the previous occupations, travel, mental habits, or reading of the sick man. F Former trains of thought, and former scenes, although often confusedly mingled, assume, to the individual himself, all the vividness of existing realities. "I saw," says De Quincey in his Confessions of an Opium Eater, "as I lay awake in bed, vast processions, that passed along in mournful pomp; friezes9 of never-ending stories, 10 that to my feelings were as sad and solemn as if they were stories drawn from times before Edipus or Priam, before Tyre, before Memphis; and, at the same time, a corresponding change took place in my dreams; a theatre seemed suddenly opened and lighted up within my brain, which presented nightly spectacles of more than earthly splendor." 9. What are called "apparitions," or spectral appearances, physiology explains upon satisfactory scientific principles. They arise sometimes from a disturbance of the retina11 alone, which gives a false interpretation of present impressions, sometimes from the vivid recalling of old images which have been stored up in the brain, but which the mind then looks upon as present realities, and sometimes the two causes unite to produce the effect. Upon these principles, the mind, in apparitions, could never see any thing absolutely new to it. And such are the facts. Thus the Greeks and the Romans were just as liable to disorders of the nervous system as we are; but to them supernatural appearances came under the mythological forms of their heathen divinities. The ascetics 12 of the Middle Ages saw phantoms of the Virgin and the saints, for these were the objects which their minds most dwelt upon; and at a later period, in Northern Europe, fairies, brownies, and Robin Goodfellows were the phantoms most frequently seen. In the Middle Ages, spectres of African negroes were common enough; but at that period no man had ever witnessed one of an American Indian, yet these, in their turn, prevailed after the voyage of Columbus. They were no strangers to our early colonial settlers. 10. One class of apparitions—those of the dead-has survived all changes of creed and superstitions, as we might reasonably suppose would be the case. But even here, as the phenomena consist merely of the emergence of old images, and new combinations of them, nothing absolutely new was ever seen in them. The Roman saw the shade of his friend clothed in the well-known toga :13 the European sees his in the modern garb; and the spirit of Maupertuis, 14 which stood by the bay-window of the library at Berlin, had on knee-breeches, silk stockings, and shoes with large silver buckles. If these apparitions existed elsewhere than in a diseased brain, is it not singular that, amid the awful solemnities of the other world, they should so faithfully have preserved the fashions of the present? Science is a great dispeller of superstitious fancies. 1 IN-VŎL'-UN-TA-RY, independent of the will. 10 STO'-RIES, lofts, or sets of rooms rising one 2 E-RAD'-I-CA-TED, rooted out; destroyed. above another. 3 SPĚC'-TRAL, having an indistinct or ghostly 11 RET-I-NA, the net-like membrane at the appearance. back of the eye which receives the image of external objects. See p. 83. 4 DE-TE'-RI-O-RATE, impair; injure. 5 IN-OR-GAN-I€, without the organs or instruments of life. 6 GĂNGʻ-LI-Ä, nerve bundles. 12 AS-CET'-IC, one who practices undue rigor or self-denial in religious things. 13 To'-GA, a kind of gown. 7 OP'-TIC NERVE, the nerve of vision, run-14 MAU-PER-TUIS' (Mo-per-'w'), a celebrated ning from the eye to the brain. 8 CON-TOUR, outline of a thing. 9 FRIEZE, in architecture, a part of the entablature. See p. 282. French academician-born in 168-died in 1759. For a long time he was president of the Royal Academy of Sciences at Berlin. LESSON XVII.—A DREAM, AND ITS EXPLANATION. DRAPER. 1. Not only may old impressions and ideas be so vividly recalled as to be presented to the mind with all the force of existing realities, but in this manner dreams are sometimes repeated; and although there is nothing strange in this, but what we should suppose would happen frequently, yet the ignorant often regard such phenomena as something bordering on the supernatural. For the following account, given by a physician, of one of the most marvelous dreams of this character, and its explanation on physiological principles, we are indebted to the work of Dr. Draper. 2. "When I was five or six years old," says the narrator, "I dreamed that I was passing by a large pond of water in a solitary place. On the opposite side of it stood a great tree, that looked as if it had been struck by lightning; and in the pond, at another part, an old fallen trunk, on one of the prone2 limbs of which was a turtle sunning himself. On a sudden a wind arose, which forced me into the pond; and in my dying struggles to extricate myself from its green and slimy waters I awoke, trembling with terror. 3. "About eight years subsequently, while recovering from a nearly fatal attack of scarlet fever, this dream presented itself to me again, identical in all its parts. Even up to this time I do not think I had ever seen a living tortoise or turtle, but I indistinctly remembered there was a picture of one in the first spelling-book that had been given me. Perhaps, on account of my critical condition, this second dream impressed me more dreadfully than the first. 4. "A dozen years more elapsed. I had become a physician, and was now actively pursuing my professional duties in one of the Southern States. It so fell out that one July afternoon I had to take a long and wearisome ride on horseback. It was Sunday, and extremely hot; the path was soli |