Night-mare, a disease consisting in an oppression of the chest, so very violent that the patient cannot speak, or even breathe. The word is derived from the Latin, incubare, to lie down on anything and press it. The Greeks call it ἐπικάρπης, saltores, leaper, or one that rushes on a person.

In this disease the senses are not quite lost, but drowned and astonished, as are the understanding and imagination; so that the patient seems to think some huge weight thrown on, and ready to strangle him. Children are very liable to this distemper; and so are fat people, and men of much study and application of mind. It is a result of dyspepsia.