First then, this disease attacks always during sleep. This is a truth of which I am now well assured, although frequently the evidence of my senses has apparently produced a contrary conviction. Whatever may be the situation of the patient at the moment previous to the invasion of the disease, he is at that moment asleep, although the transition from the waking to the sleeping state may be so rapid as to be imperceptible. I will explain this part of the subject more fully by and by, at present we will assume the fact, and proceed to enumerate the symptoms. If the patient be in a profound sleep, he is generally alarmed with some disagreeable dream; he imagines that he is exposed to some danger, or pursued by some enemy which he cannot avoid; frequently he feels as though his legs were tied, or deprived of the power of motion; sometimes he fancies himself confined in some very close place, where he is in danger of suffocation, or at the bottom of a cavern or vault from which his return is intercepted. It will not unfrequently happen, that this is the whole of the sensation which the disease, for the time, produces, when it goes off without creating any further annoyance: the patient either falls into an oblivious slumber, or the alarming dream is succeeded by one more pleasant. In this case the disease is not fully formed, but only threatens an invasion; it proves however that the pre-disposition to it exists, and that the person is in danger of it. But when the paroxysm does actually take place, the uneasiness of the patient in his dream rapidly increases, till it ends in a kind of consciousness that he is in bed, and asleep; but he feels to be oppressed with some weight which confines him upon his back and prevents his breathing, which is now become extremely laborious, so that the lungs cannot be fully inflated by any effort he can make. The sensation is now the most painful that can be conceived; the person becomes every instant more awake and conscious of his situation: he makes violent efforts to move his limbs, especially his arms, with a view of throwing off the incumbent weight, but not a muscle will obey the impulse of the will: he groans aloud, if he has strength to do it, while every effort he makes seems to exhaust the little remaining vigour. The difficulty of breathing goes on increasing, so that every breath he draws, seems to be almost the last that he is likely to draw; the heart generally moves with increased velocity, sometimes is affected with palpitation; the countenance appears ghastly, and the eyes are half open. The patient, if left to himself, lies in this state generally about a minute or two, when he recovers all at once the power of volition: upon which he either jumps up in bed, or instantly changes his position, so as to wake himself thoroughly. If this be not done, the paroxysm is very apt to recur again immediately, as the propensity to sleep is almost irresistible, and, if