Part 3

Of all the modes of solving difficulties, which mankind have ever had recourse to, this is certainly the least _philosophical_. In the present age however it appears to be considered still more _unphilosophical_ to acknowledge that any phenomenon, however extraordinary, is above our comprehension.

I have been rather prolix on this subject, because I do not remember to have seen any correct account of it in any writer, although the circumstance of seeing spectres during the paroxysm of Incubus is noticed by the most ancient medical writers and others, both Greek and Roman; many of whom attributed the whole phenomenon of _Ephialtes_, or _Incubus_, to the agency of Dæmons. This affection has likewise been noticed by St. Augustine as well as other Fathers of the Church, who considered it to be the work of Dæmons, and speaks of it as a thing common in those days.--ST. AUGUSTIN. _De Civitate Dei_, lib. 15. c. 23.--“_Dæmones, scilicet, qui mulieribus se commiscent, et ab incubando_ INCUBI _dicuntur, sicuti, qui viris, et patiuntur muliebria_, SUCCUBI.” “_Sunt nonnulli, qui hoc malum Incubi nomen accepisse putant, ex eo, quod Ephialte laborantes, opinantur, hominem qui illos opprimit, turpis libidinis usum ab iis exigere, seu una cum illis concumbere._”--SENNERTUS, Tom. ii. Liber i. part. 2. Cap. xxix. _de Incubo_.

_Vide quæ supra de Priapismo memoravimus; necnon de Cordis palpitatione quæ revera Priapismi etiam somnorumque supradictorum causa mihi esse videtur; impulsum est nimirum in arterias pudicas plus sanguinis quam per venas revehi potest, unde partes genitales vellicantur et stimulantur, somniisque venereis, non tamen sine horrore quodam, ansa præbetur._

There is a symptom, said by Etmuller, and some others of the ancient medical writers, to occur frequently in this disease, but which I have never met with; that is, the appearance of red, or livid, or purple spots upon the limbs and body, but especially on the thighs.--These are said to remain till morning, and then disappear.

The following case is related by that celebrated Physician:

“_Historiam Incubi magis ad epilepticos, quam paralyticos affectus referendi, subjungam: Puella xviii. annorum cachectica, et cui nondum menses fluxerant, indeque nonnihil asthmatica, ex narrationibus, crebrioribus servæ seu famulæ, primum imaginationem Incubi concipit, cum ab illa sæpius audivisset, se quavis nocte Incubo corripi, et istud mali ab alio concitari. Jam utut hæc ipsa dimissa fuerit, illa tamen mox ab hujus discessu Incubo corripi cepit; nempe omni nocte præcise horâ secundâ incipit quiritare, hinc mox sensu et motu privata jacet, donec successivè ad se redeat, quo tempore sudore madet, et hinc inde in corpore, maculas magnas rubras, præsertim in femoris parte carnosa observat. Hæc quavis nocte eodem præcisè tempore redeunt. Ergo suspicabar Incubum esse revera convulsivum in subjecto hypochondriaco cachectico. Dedi Tartari Emetici, g. iij. qui parum operabatur, et hinc quovis mane de Pulvere Cachectico seu Croco Martis Aperitivo largam dosin prohibendo acida. Successus fuit, ut post aliquot dies noctesque, Incubus tardiùs affligeret, hora tertia, hinc quarta, tandem quinta matutina, tandem per biduum, penitus deficeret, quo transacto hora quinta matutina malum redit, sed absque maculis. Propino Vomitorium liquidum, cujus usu cum copiosa mucosa rejecisset, non rediit Incubus. Suasi ut Elixyr Proprietatis imposterum continuaret, certus, modò primæ viæ a cruditatibus acido pituitosis essent liberæ, et hinc menses comparerent, eam pancraticè valituram._”

To those to whom the disease is habitual, there remains after the paroxysm a sense of lassitude, heaviness, drowsiness, and a continued predisposition to the affection; so that if they indulge in sleep, they are almost certain of a return of the symptoms. It is not easy to describe this state, but the patient is very sensible of it, and every one who is subject to this affection, can easily tell when the predisposition to it exists.

This state of predisposition I have often experienced during the day, but this only happens when the disease has arrived at a very great height. It is attended with a sensation of something like a weight and great uneasiness about the heart, requiring often a sudden and full inspiration of the lungs, and obliging me to rise up and walk about a little, in order to be clear of it. If in this state, I sit down to read or write, the propensity to sleep is so great that in the space of a few seconds, after having directed the whole attention of the mind to the object on which I chance to be employed, I find my thoughts involuntarily carried away to distant scenes, and that I am in reality dreaming, from which state I am only roused by a sense of something like suffocation, and the unpleasant sensation before mentioned about the heart. This is relieved for the moment by a sudden and strong inspiration; but if the sedentary employment be continued, it quickly returns. If in this state I yield to the strong inclination to sleep, a severe paroxysm of Incubus is the inevitable consequence, and that in the course of a very few minutes. When this peculiar sensation about the heart occurs in bed, there is no recourse left but rising instantly, and walking it off, or having recourse to such medicines, if they are at hand, as experience has taught me are efficacious in the removal of it.

These are I believe the most common phenomena attending Night-Mare. I must beg leave, however, to remind the reader, that there are various degrees of this affection, as well as of the predisposition to it; all of which more or less disturb the rest, and derange the system. All unpleasant dreams may be considered as certain modifications of this peculiar affection; such as falling down precipices, or standing on their brink, or being in the midst of a torrent, or in imminent danger of our lives. If these ideas continue long, they generally produce a degree of consciousness that we are asleep, which is succeeded by an attempt to evade the danger by waking ourselves, which constitutes real Night-Mare.

There is, however, another kind, which differs a little from this I have been describing, but is nevertheless to be considered as a modification of Night-Mare, arising from the same cause, and requiring the same remedies; for which reason I shall include it in my History of that disease. I mean that undescribable terror which some persons feel in their sleep, and which frequently obliges them to vociferate loudly, and generally to start with violence, or sometimes even to jump out of bed. This terror is often, perhaps mostly, accompanied by some really terrific dream. This is not always the case, however, and when it does happen, the dream is rather to be considered as the effect of the terror, than the cause of it. I have frequently found this terror to be connected with some object, not at all in itself terrific; as for instance, a cat or a dog, or sometimes a little child which I had been contemplating in my dream for some time without any dread or terror, has all at once become an object of the utmost horror and alarm, and that without at all changing its appearance or attitude. A sudden panic has struck me with a degree of terror, which I am convinced nothing on earth could produce in me when awake; and which obliges me to vociferate with uncommon vehemence, and to start with so much violence as generally to wake myself immediately, and frequently great part of the family beside. It would be impossible by any words, to convey an adequate idea of the terror felt during this affection: the patient continues to feel it for several minutes after he is awake; at least it requires some little time for even a strong mind to recover its tranquillity. I have always observed in my own case, as well as in all those I have had the opportunity of investigating, that this kind of affection is universally accompanied with a sensation called shivering; not precisely of that kind which accompanies the paroxysm of ague, but that momentary sensation of shivering which people are apt to feel on hearing any tale of horror related, or frequently indeed, without any evident cause whatever. It is a vulgar opinion, that this shivering takes place whenever any one is walking over the future grave of the person who feels it. This kind of shivering is, at all times, accompanied with some degree of horror, and that has probably been the reason of the superstitious opinion above mentioned. Hence also the common expression, on hearing a tale of horror, that _it makes the blood run cold_; which is precisely the sensation of the person, both in the dreams themselves which we are speaking of, and for some little time after waking out of them. This sensation is always referred to the spine, and appears to descend from the neck to the loins. The cause of it is not very easy to explain; it evidently belongs to that class of sensations and affections which we call nervous, and appears in this case to be the immediate cause of that terror which invades us in sleep, by inducing some idea of great horror.

Amongst all the subjects of terror which infest the human mind, there is none so powerful as the idea, which is generally imbibed at a very early period of life, respecting ghosts and supernatural appearances; and there are comparatively few persons who, when alone and in the dark, are perfectly free from them. In sleep, however, we are all much more timid than when awake. I believe every person’s experience coincides in this opinion: hence it arises, that the idea of ghosts and spectres being the idea which inspires us with the greatest terror, is that which most readily and frequently presents itself to the mind, when the nervous system is suddenly agitated during sleep; a state when all objects of fear act with increased force. Whatever may be the cause which induces this kind of shivering during sleep, the shivering itself appears to me evidently to be the immediate cause of the terror, and the accompanying terrific dream; and this I conceive to happen from association; for as this shivering is the kind of involuntary sensation we feel when suddenly alarmed, or even when we hear or read a tale of terror, the feeling itself becomes so associated with terror, as always to recal to the mind, even in sleep, the idea of it; the sensation being the same as if the nerves had actually received some terrific impression; and as the imagination has full play when asleep, it is seldom long in furnishing the terrific object.

I have known these dreams to be succeeded by an hysterical affection, of involuntary laughing and crying; and they are, I believe, in all cases attended with a great degree of nervous irritability.

It will sometimes happen in this case, as in the preceding, that the patient does not awake from his dream, notwithstanding that his vociferations have been loud enough to wake all those who may sleep near him. When this happens he seldom or never has any recollection of his terror, and feels greatly surprised when told of the alarm he had given to others. The moment the shivering which produced the terror has ceased, this likewise ceases; and seldom leaves in the mind, any trace of its having existed: in this respect it differs greatly from the Night-Mare, in some others it appears to have some considerable affinity to that affection.

It is not uncommon for persons affected with these terrific dreams to leap out of bed, and attempt to escape from some imaginary danger by flight. Many instances have occurred of persons jumping immediately out of a high window under these circumstances: the same accident very lately occurred to a youth in this metropolis.

There are several other accidents to which our sleep is liable, but as they differ in their nature considerably from Night-Mare, we shall not here take any notice of them.

I shall now speak of the persons who are subject to Night-Mare, before entering into an investigation of its causes.

This affection may at some time or other occur to any person whatever, as it will for the most part be found to be the constant attendant upon indigestion: now the most healthy person in the world will sometimes meet with food which his stomach will not digest, and if he goes to sleep whilst such food is remaining in the stomach, or in the superior portion of the alimentary canal, he will certainly be affected with Night-Mare, to a greater or less degree. But a peculiar habit of body is necessary to render a person subject to it, so that it can become habitual. Many persons begin to feel its effects in very early youth; these are generally of a contemplative disposition, and of a peculiar temperament, which renders them liable to hypochondriasis and nervous diseases. To these persons the Night-Mare often becomes habitual. All who follow sedentary employments, or whose avocations keep them mostly in doors, more especially literary characters, and all studious persons, are the victims of these affections. Those likewise, who, although they do not want for air and exercise, yet are accustomed to a coarse and unwholesome diet; hence sailors are, of all classes of men, the most subject to Night-Mare and terrific dreams. All hypochondriacs, and frequently pregnant women, are amongst the subjects of these affections.

It occasionally accompanies fever and other acute diseases. I remember one patient to whom it became extremely troublesome in the last stage of consumption, who had never before in her life been affected by it. Sylvius Deleboe, who has recorded the _history_ of an epidemic disease, which raged in the city of Leyden, in the year 1669, mentions the Incubus as a very common affection in it, with which he was himself afflicted to a great degree. He describes it as accompanied with an unusual degree of somnolency, and making its attack on the accession of the febrile paroxysm. Perhaps it was something of this kind, which Cœlius Aurelianus asserts to have been epidemic at Rome. Sylvius relates that the lethargy, or propensity to sleep, was so great during the febrile paroxysm, and accompanied with so unpleasant a sensation, even when Night-Mare did not come on, that he thought proper to order himself, as well as his patients, to be kept awake by the attendants. He describes it thus: “_Non tantum cum Incubo, sed absque ipso gravis fuit ægris multis Somnus profundus, et insomniis multifariis molestus_.” In another place, “_Nec tantum sola difficili respiratione laborarunt multi, verum etiam Incubo nonnulli, et inter ipsos ego quoque; qui cum paroxysmis febrilibus repetens atque somnolentiam simul excitans, fuit mihi valdè molestus, donec ipsum agnoscens rogarem adstantes, ut tamdiu somnum in quem tam valde propendebam, interturbarent ac impedirent, donec paroxysmo declinante in somnum suavem ac commodum inciderem absque omni incubo_.” Sylvii Praxeos. Med. Tract. x.

It sometimes appears in very early life, in which case it generally sticks close to the patient, almost all his days. In some, however, such a change in the constitution takes place at puberty as destroys altogether that predisposition to this affection, which existed in early life.

Females appear much less subject to it, than males, though by no means exempt. Of these, virgins and pregnant women are more particularly liable to its attacks, as well as all those who are much visited by hysterical affections, constipation, and flatulency. It is sometimes also found to accompany the _chlorosis_ or green sickness. On the whole, however, it is of comparatively rare occurrence amongst females.

Neither is this disease very common in advanced life, unless where corpulency, or a tendency to lethargy exists. In those cases however where it does occur, it is more to be dreaded than in youth or middle age. It is no unfrequent attendant on asthmatic persons.

The opinions of medical men with respect to the immediate cause of this disease, or what by them is termed its proximate cause, have been various and discordant, as generally happens in all obscure investigations. In all probability every one of them are wrong, so that it can be of little utility to inquire into them. There is however one idea, which seems to be more universally adopted than any other, and which deserves notice; it is, that this affection is produced by a cause purely mechanical, and depending on the position of the body. Some plausible theories have been formed on this supposition, by assigning to the different thoracic and abdominal viscera, certain relative positions which would occasion a temporary pressure upon the organs of respiration, or upon some branch of the intercostal nerves. With respect to this mechanical pressure, arising from any imagined position of the patient, what I have already said on that score, renders this hypothesis vain, for there is no position in which it is possible for a person to fall asleep, in which I have not been attacked by Night-Mare. Neither is there any more dependence to be placed on the generally received opinion, of the disease being induced by a full stomach. It may naturally be supposed, that any person labouring under this affection to the degree which I have stated, although I have as yet given a very feeble idea of its extent, would take every possible precaution to keep clear of the causes, which were so generally believed to have produced it. I religiously abstained, for many years from eating any thing after dinner, and took dinner also at as early an hour as two o’clock. It was during this period that I suffered most from the disease. I think I may safely assert, that for more than twenty years, I have never once, to the best of my recollection, fallen asleep on my back, or ever found myself in that position on waking. When night after night has been rendered miserable by this enemy of repose, I have had recourse to every expedient which deep reflection could suggest. The perpendicular position of the body, I have found by experience to be the worst in which a paroxysm of Night-Mare can be borne. The difficulty of respiration, and all the other symptoms are greatly aggravated, and an additional one is felt, which greatly increases the sufferings of the patient; it is a perpetual dread of falling, which appears inevitable, and which prevents the patient from struggling so much as he would do if in a horizontal position. Next to this is the position of sleeping with the body bent forwards, and the head reclining with the face downwards on a table: in this last position, the difficulty of inflating the lungs is extreme. I have never been able to discover that any great difference arose between sleeping on the right or left side. I have always considered it as a matter of indifference. Although it is possible to render the paroxysm of Night-Mare more tolerable by any particular position of the body, yet I am well assured that no position will secure a person from its attacks, to whom it has once become habitual. I slept for some time in an easy chair, and found the disease greatly aggravated by it.

There must however be some reason for the universal opinion that it always attacks persons lying on the back. I was for a long time of opinion myself, that I was always lying in that position when the paroxysm came on, but as the disease gained strength, and the paroxysms hung more pertinaciously upon me, I became more perfectly awake, so as to be able to discover more accurately the position in which I was lying, and I found that little faith was to be given to the sensations that may occur during Night-Mare, as they are the most deceitful of all evidences. It appears to be one of the symptoms almost inseparable from the disease, that the patient should appear to himself to be kept down upon the back by some external force. This sensation I have almost always felt, even when I have had the evidence of other people, as well as my own conviction when awake, that I was in reality lying on the side. I cannot help suspecting that many others have been deceived in a similar manner, and thus made to believe, that they never had the Night-Mare except when sleeping on their backs. There is also another sensation which is very apt to deceive the patient, that is, on the paroxysm going off, and the moment of his recovering the power of volition, a great confusion of ideas always takes place, and a person to whom the Night-Mare is not very familiar, generally imagines that he has recovered himself by some effort of his own, frequently by turning from his back to his side, sometimes by sitting upright in bed. These things are all extremely fallacious; there is no trusting to the senses during a paroxysm of Incubus; nothing short of the evidence of another person ought to satisfy the patient. I have often been thoroughly convinced in my own mind that I had succeeded in throwing the bed-clothes off my breast, and by that means gained relief, and not unfrequently, that I had risen from bed, and opened the window to admit air; yet both these ideas have been proved to be incorrect. I have often felt very certain that my right arm was out of bed, and that I had moved it about; but on waking thoroughly, I have found it under the bed-clothes, and in a situation in which it could not have been moved. I cannot help thinking then, that the universal idea of its attacking persons exclusively lying on the back, is founded on an error, arising out of the ordinary sensations of the patients themselves, who have always that idea, let them be in what position they will. Several persons, subject to habitual Night-Mare, have become convinced of the truth of this observation, which I had made to them, after attending more closely to their real situation during the continuance of, and immediately after the paroxysm. I have also convinced one or two medical friends, who were extremely sceptical on that point, that it would attack me in any position, by going to sleep before them, on a chair, or sofa, when my own feelings have indicated the certainty of attack, if I should indulge for a few moments the propensity I felt to sleep.

Neither is it necessary for the stomach to be filled with food, in order to produce Night-Mare, as is evident from what I have stated above with respect to the abstinence I observed during the period in which I suffered most from this affection. Experience has taught me that I may eat heartily of some kinds of food, just before going to bed, with impunity; whilst the smallest quantity of some other will inevitably bring on the disease, in spite of all the precautions that can be taken.

Thus then we must give up every explanation of the phenomena which occur in this disease, founded upon principles purely mechanical, however plausible they may appear. Neither is the opinion of Darwin more correct, that the Night-Mare is nothing more than a consciousness of the suspension of the power of volition, and a desire to recover that power. If so, it would differ little from sleep itself; or, however fatiguing it might be to the mind, it could not occasion any derangement in the functions. The breathing and the circulation would go on without any interruption, as in sleep; nor would there be any thing that could produce the sense of oppression on the breast. Darwin was well aware of this difficulty, and therefore chose rather to contradict the generally received opinion of oppression and difficulty of respiration. There is no doubt whatever of the difficulty of breathing, which any one may assure himself of, if he could have the opportunity of seeing a patient during the paroxysm of Night-Mare. I have taken considerable pains to assure myself of this circumstance from the evidence of other persons.