ALthough I have assign’d the supine position of the Body, and the pressure of the Heart upon the Pulmonary Veins and the left Auricle, as the immediate Causes of this Disorder; yet it is necessary to consider several pre-disposing circumstances, which may render some persons more subject to it than others, who may perhaps sleep sometimes on their Backs, and escape it.
The general primary Causes of this Disease are a Plethora, or a too great quantity of Blood, a viscidity or tenacity of the Fluids, and a weakness or inertia of the Solids. Hence, young persons of gross full habits, the robust, the luxurious, the drunken, and they who sup late, are most subject to the Night-mare19. Also Women who are obstructed; Girls of full, lax habits, before the eruption of the Menses; of which I have collected the following Cases,
CASE I.
A young Lady, of a tender, lax habit, about fifteen, before the Menses appear’d, was seiz’d with a fit of this Disease, and groan’d so miserably that she awoke her Father, who was sleeping in the next room. He arose, ran into her chamber, and found her lying on her Back, and the Blood gushing plentifully out of her Mouth and Nose. When he shook her, she recover’d, and told him, that she thought some great heavy Man came to her bedside, and, without farther ceremony, stretched himself upon her. She had been heard moaning in sleep several nights before; but, the next day after she imagin’d herself oppress’d by that Man, she had a copious eruption of the Menses, which, for that time, remov’d all her complaints.
CASE II.
A young Lady, about twenty, of a full, sanguineous habit, and lax system of Fibres, labour’d under an obstinate obstruction of the Catamenia for six months. About six weeks after her first period elaps’d, she had a severe fit of the Night-mare, and next morning she spit near a pound of Blood, part of which was coagulated. She complain’d of an anxiety and oppression in her Breast, for several days afterwards. She soon grew well, and continued so ’till a month had pass’d, when the Night-mare return’d, and was succeeded by a spitting of Blood; but the second fit was not so severe as the first. She had periodical fits and discharges of this kind, ’till, by proper remedies, the redundant streams were convey’d through their usual channels, which at the same time carried off the cause and heavy effect of the Nightmare.
CASE III.
A robust servant Girl, about eighteen years old, was severely oppress’d with the Night-mare, two or three nights before every eruption of the Menses, and us’d to groan so loudly as to awake her Fellow-servant, who always shook or turn’d her on her Side; by which means she recover’d. She was thus afflicted periodically with it, ’till she took a bedfellow of a different sex, and bore Children.
CASE IV.
“A Woman, fifty years old, of a good, full, fleshy, strong habit of Body, after her Menses stop’d, was constantly tormented with this Disorder20.”
I might add many more instances of this kind, to shew, that the fair sex is subject to the severe insults of this oppressive Disease; but hope these are sufficient to excite the attention of others to make observations of this sort, which are the more necessary, as they have been too much neglected by writers on this subject.
When Women pass the fruitful seasons of life, and the delicate uterine Tubes, contracting themselves, become too rigid, and resist the impetus of the Fluids so as to prevent the usual discharges; then the Fluids, which were formerly periodically evacuated, are amass’d, and collected in the Body, and occasion a Plethora. Hence, Women, about that time, often grow fat, heavy, and sickly, and become more subject to the Night-mare; because the Heart, swell’d with redundant Blood, will bear more heavily on the Pulmonary Veins and left Auricle, when they happen to sleep in a supine position.
Experience declares, that there is not a more frequent primary Cause of the Night-mare than heavy suppers of tough animal food, and large quantities of soft, thick malt liquors, which distend, and lie long in the Stomach; whose pressure may contribute, in many respects, to produce this Disorder.
1st. Its pressure on the Aorta Descendens will determine a greater quantity of Blood than usual into the Arteries that belong to the Head; and as these turgid vessels run contiguous to the trunks of the Intercostal and eight pair of Nerves, they may perhaps compress them so as to render the Heart, &c. paralytic.
2d. By occupying a large space in the Abdomen, it hinders the full contraction of the Diaphragm, and thus diminishes the cavity of the Thorax, prevents the necessary expansion of the Lungs, and consequently obstructs the motion of the Blood through them.
3d. Anatomy informs us, that the Diaphragm is not perpendicular to the Spine of the Back, but forms an acute angle with it, and is extended obliquely upwards to the Sternum21. Hence, in a supine position of the Body, the Diaphragm may be considered as an inclin’d plane, upon which the surcharg’d Stomach must rest; and its weight on this part will increase the pressure of the Heart on the Pulmonary Veins, as it is connected to the opposite side of the Diaphragm by the Pericardium.
Every one knows that a hearty meal disposes People to sleep. This effect was commonly attributed to the pressure of the Stomach on the descending Aorta: but Doctor Stuart has oppos’d that theory22. Doctor Haller has seconded him, and has given his reasons for it. He says, “Si exquisitiori Anatome in situm Ventriculi & Aortæ inquisiveris, reperies vix unquam Aortam a Ventriculo comprimi posse. Dum enim distenditur, antrorsum recedit, et Curvaturam parvam retrorsum ostendit Aortæ, quæ ea Curvatura, interjecto Pancreate, comprehenditur23 ”
This is certainly a just account of the appearance of the Stomach, when it is distended in a dead Body, where the Integuments of the Abdomen, and all resistance to the Stomach’s rising, is taken away: but, if we consider the Stomach distended by any means in a living Body, where these Integuments still remain in an active state, and resist the motion of the Stomach forwards and upwards; then a great part of its pressure must fall on the Aorta, and confirm the old opinion. That part of the Diaphragm, through which the Oesophagus passes, must be the center of motion in this case; and allowing, that the Stomach moves a little upwards and forwards, in a distended state, yet, as the Abdominal Viscera are in such a fluid or fluctuating condition, that place, which may be deserted by the distention of the Stomach, will be fill’d up by the Pancreas; and by this means, the Aorta may suffer as great a pressure as if it was immediately in contact with the Stomach: the argument, which that industrious Gentleman adds, may be owing to the peculiarity of his own constitution; viz. “Imo vero aucti a pastu veneris stimuli demonstrant, eo tempore motum Sanguinis in Aortam descendentem potius majorem esse, quam minorem24 ”.
Doctor Haller seems to have levell’d the force of this argument against a full Stomach being any cause of the Nightmare; but I might mention many facts here to prove the contrary, and among the rest, might add my own case; but, to avoid prolixity, I shall confine myself to one instance.
A corpulent Clergyman, about fifty years old, who is very fond of strong beer and flesh suppers, but so subject to the Night-mare, that he is obliged to stint himself to a certain quantity every night; whenever he happens to take an over-dose, he groans so loudly that he often awakes all the People in the house. He has assur’d me, that, in these fits, he imagin’d the Devil came to his bedside, seiz’d him by the Throat, and endeavour’d to choak him. Next day he observ’d the black impressions of his hard Fingers on his Neck. After being at a wedding or christening, he never escapes it; and his Servant is oblig’d to watch him all the next night, and rescue him from the Paws of Satan, whose dreadful approach always makes him roar loud enough to awake the Servant, if he should happen to be asleep. The Ser vant told me, he always found his Master lying on his Back in the fit.
Hoffman says, “25 Plethoricos omni cura fugere opportet decubitum supinum, facile enim Incubo premuntur, cujus causa a Sanguinis stagnatione in Pulmones deducenda est.”
Doctor Haller assigns a different reason for heavy suppers preventing rest, viz. “26 Sed etiam cibi immeabiles particulæ in Cerebro minus facile trajactæ, comprimendo Medullam somnum minus benignum faciunt.”
It is remarkable, that this Disorder attacks People only in sleep; which, Doctor Young says27, is owing to the effect that sleep has in increasing all the symptoms of a Plethora. It is true, that sleep retards the motion of the Blood, and checks the serous secretions. “28.In vasis vero serosis, Lymphaticis et Nervosis circulatio parva, et sæpe nulla est.”
There is no occasion to go about proving that the secretion of urine is lessened in bed, for common experience sufficiently evinces it. And it appears, by the experiments of Doctor Robinson29 and Gorter30, that perspiration is considerably less in the night than in the day. It must be allow’d, that the heat of the bed-cloaths will rarify the Blood, and also contribute to an universal distension of the Vessels: but all these seem to be rather the effects of lying quiet in a warm bed, than of sleep alone. If so, People might be as readily seiz’d with the Night-mare while they are awake in these circumstances, as when they are asleep, which never happens.
I really can find no way of accounting for this Phænomenon, unless we have recourse to the Soul, or that ac tive principle within us, whose operations, during sleep, are either greatly impeded, or altogether suspended. It is therefore less sensible of any uneasiness in the Body than when we are awake, and the faculties of the Mind are in action, which is compell’d, by some innate necessity, to avoid any pain, as soon as it perceives it in the Body.
While we are awake, lie on our Backs, and feel any uneasiness in that position, we immediately alter it: but, in sleep, we are not so soon conscious of the Blood’s stoppage in the Lungs, nor have we the means of removing that dangerous obstruction so much in our power, because the voluntary motions are then suspended, without which, the position of the Body cannot be changed, nor the cause of the obstruction remov’d.
The insensibility of the Lungs too may contribute to render the obstruction greater, before the Mind becomes conscious of it; for we don’t find, that obstructions and inflammations of the Lungs are attended with such an acute pain, as when these Disorders attack other parts of the Body, the Liver, Spleen, and Omentum excepted.
The Night-mare may sometimes seize very plethoric Persons, when they don’t lie directly on the Back; for part of the Heart’s weight may fall on the Pulmonary Veins, in a lateral position of the Body.
By way of a brief recapitulation of what has been offer’d concerning the Causes in general of this Disorder, I shall conclude this Chapter with the following corollaries.
Cor. 1. That they who have a very sensible system of Fibres, and are soon affected by a stimulus, are least subject to the Night-mare.
Cor. 2. That sluggish, inactive constitutions are most liable to it.
Cor. 3. That the severity of the fit will be always proportional to the sen sibility of the Fibres, and the quantity of Blood.
Cor. 4. That the duration of a fit will be proportional to the sensibility and vigour of the constitution.
Cor. 5. That they who sup sparingly, and never sleep on their Backs, are seldom or never afflicted with it.
Cor. 6. That it is most common in those seasons of the year, which most increase the volume of the Fluids: hence spring and autumn are its most fertile periods.