ON THE INCUBUS, OR NIGHT-MARE. J. M‘Creery, Printer, Black Horse Court, London. A TREATISE ON THE INCUBUS, OR Night-Mare, DISTURBED SLEEP, TERRIFIC DREAMS, AND NOCTURNAL VISIONS. WITH THE MEANS OF REMOVING THESE DISTRESSING COMPLAINTS. BY JOHN WALLER, SURGEON OF THE ROYAL NAVY. LONDON: PRINTED FOR E. COX AND SON, ST. THOMAS’S STREET, BOROUGH. 1816. INTRODUCTION. The enjoyment of comfortable and undisturbed sleep, is certainly to be ranked amongst the greatest blessings which heaven has bestowed on mankind; and it may be considered as one of the best criterions of a person enjoying perfect health. On the contrary, any disturbance which occurs in the enjoyment of this invaluable blessing, may be considered a decisive proof of some derangement existing in the animal economy, and a consequent deviation from the standard of health. Indeed it is astonishing how slight a deviation from that standard may be perceived, by paying attention to the circumstance of our sleep and dreams. This may be more clearly demonstrated by attending carefully to the state of persons on the approach of any epidemic fever or other epidemic disease, and indeed of every kind of fever, as I have repeatedly witnessed; when no other signs of a deviation from health could be perceived, the patient has complained of disturbed rest and frightful dreams, with Night-Mare, &c. Hence the dread which the vulgar, in all ages and countries, have had of what they call _bad_ dreams; experience having proved to them, that persons, previously to being attacked with some serious or fatal malady, had been visited with these kind of dreams. For this reason they always dread some impending calamity either to themselves or others, whenever they occur; and, so far as relates to themselves, often not without reason. Frightful dreams, however, though frequently the forerunners of dangerous and fatal diseases, will yet often occur when the disturbance of the system is comparatively trifling, as they will generally be found to accompany every derangement of the digestive organs, particularly of the stomach, of the superior portion of the intestinal canal, and of the biliary system. Children, whose digestive organs are peculiarly liable to derangement, are also very frequently the subjects of frightful dreams, and partial Night-Mares; which are frequently distressing enough to them. They are still more so to grown up people, as they generally arise from a more serious derangement of the system. Those who are subject to them will agree with me in opinion, that they are by no means to be ranked amongst the lesser calamities to which our nature is liable.