It is a general, but, as it appears to me, a mistaken opinion, that in our ordinary dreams we judge the objects to be real. I say our ordinary dreams;--because as to the night-mair the opinion is to a considerable extent just. But the night-mair is not a mere dream, but takes place when the waking state of the brain is recommencing, and most often during a rapid alternation, a twinkling, as it were, of sleeping and waking;--while either from pressure on, or from some derangement in, the stomach or other digestive organs acting on the external skin (which is still in sympathy with the stomach and bowels,) and benumbing it, the sensations sent up to the brain by double touch (that is, when my own hand touches my side or breast,) are so faint as to be merely equivalent to the sensation given by single touch, as when another person's hand touches me. The mind, therefore, which at all times, with and without our distinct consciousness, seeks for, and assumes, some outward cause for every impression from without, and which in sleep, by aid of the imaginative faculty, converts its judgments respecting the cause into a personal image as being the cause,--the mind, I say, in this case, deceived by past experience, attributes the painful sensation received to a correspondent agent,--an assassin, for instance, stabbing at the side, or a goblin sitting on the breast. Add too that the impressions of the bed, curtains, room, &c. received by the eyes in the half-moments of their opening, blend with, and give vividness and appropriate distance to, the dream image which returns when they close again; and thus we unite the actual perceptions, or their immediate reliques, with the phantoms of the inward sense; and in this manner so confound the half-waking, half-sleeping, reasoning power, that we actually do pass a positive judgment on the reality of what we see and hear, though often accompanied by doubt and self-questioning, which, as I have myself experienced, will at times become strong enough, even before we awake, to convince us that it is what it is--namely, the night-mair.