make nightmare worthy of serious medical investigation.
In nightmare, as A. Brierre de Boismont shows, the incubus takes different forms. Sometimes the subject fancies he flies in the air. He gives the case of a distinguished writer, whom he had seen in that state, uttering inarticulate sounds—his hair bristling, his countenance full of terror. At such times he would exclaim, "How surprising! I fly like the wind! I pass over mountains and precipices!" For several seconds after awaking he still imagined himself floating in the air. Others skim over the ground, pursued or threatened by dangers.
In childhood and youth, according to the same author, the individual is upon the edge of precipices, about to fall. In later years, robbers are breaking into the house, or the victim supposes himself condemned to death. Occasionally cats, or other animals or monsters, place themselves upon the stomach. "The weight of this imaginary being stifles, while it freezes the blood with horror." While not every case of nightmare is attended with motion or sound, nightmare passes into somnambulism when the victim shrieks or leaps from his bed, or makes any motion.
Somnambulism, in its simplest form, is seen when persons talk in their sleep. They are plainly asleep and dreaming; yet the connection, ordinarily broken, between the physical organs and images passing through the mind is retained or resumed, in whole or in part. It is very common for children to talk in their sleep; also many are liable to mutter if they have overeaten, or are feverish or otherwise ill. Slight movements are frequent. Many who do not fancy that they have ever exhibited the germs of somnambulism groan, cry out, whisper, move the hand, foot,
