of "mare" is an incubus, as of a spirit which torments persons in sleep. In nightmare the mind is conscious of an impossibility of motion, speech, or respiration, a dreadful pressure across the chest, and an awful vision of impending danger. The victim sometimes realizes his peril, gathers all his forces, struggles vainly, and endeavors to shout for help. At last, by a desperate effort, he succeeds in screaming. If then some friendly touch or voice awakens him, the vision flees, and he is left stertorously breathing, perspiring, and more tired than if he had broken stone or worked in a tread-mill for as many hours as the nightmare lasted minutes. If not aroused, he may be awakened by his own screams; otherwise the incubus may not depart for a period, which, though short in actual time, seems like ages to him.
A young man under the writer's care was subject to attacks so harrowing that it was excruciating to be in the room with him during the paroxysm. Sometimes after he was awakened the terrifying vision would not wholly fade away for three quarters of an hour or more, during which his shrieks, groans, appeals to God, and the expression of unutterable agony upon his face were terrible. In the city of Philadelphia, a lad, having been exceptionally healthy from birth, was attacked with nightmare when fourteen years old. After a few seizures his father slept with him, for the purpose of awakening him should there be occasion. One night the father was startled by the voice of his boy calling in terrified tones, "Pop! Pop! I'm afraid!" He felt the hand of his son nervously clutching his wrist. Then the boy fainted, and died instantly. The post-mortem examination showed a large clot of blood about the heart, caused by paralysis due to fear. There is reason to believe that such instances are numerous enough to
