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.