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-mare[19]. 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 Disorder[20].”