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 Sternum[21]. 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 theory[22]. 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, comprehenditur[23]”
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 minorem[24]”.
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.