Sleep walking or night wandering, known also by its Latin name of noctambulism, is a well-known phenomenon. Somnambulism is not so good a term for it, since that signifies too many things. In sleep walking a person rises from his bed in the night, apparently asleep, walks around with closed or half opened eyes, but without perceiving anything, yet performs all sorts of apparently purposeful and often quite complicated actions and gives correct answers to questions, without afterward the least knowledge of what he has said or done. If this all happens at the very time and under the influence of the full moon, it is spoken of as moon walking or being moonstruck. Under the influence of this heavenly body the moonstruck individual is actually enticed from his bed, often gazes fixedly at the moon, stands at the window or climbs out of it, "with the surefootedness of the sleep walker," climbs up upon the roof and walks about there or, without stumbling, goes into the open. In short, he carries out all sorts of complex actions. Only it would be dangerous to call the wanderer by name, for then he would not only waken where he was, but he would collapse frequently and fall headlong with fright if he found himself on a height.