A gentleman of a nervous and irritable disposition informed me that he had dreamed of being in heaven and being dazzled by the brilliancy of everything around him. So great was the light that he hastened to escape from the pain which it caused in his eyes. In the efforts which he made he struck his head against the bedpost, and awoke to find that the fire which he had left smouldering on the hearth had kindled into a bright flame, the light from which fell full in his face. Another, who had been under my care for epilepsy, dreamed that his room was entered by burglars, and that with lighted candles in their hands they were searching his drawers and trunks. He related his dream the following morning, and was told by his mother that she had gone into his room the previous night, and had held a lighted candle close to his face in order to see whether or not he was sound asleep. No one has more philosophically studied the mode of production of dreams than M. Maury[83] in his remarkable work to which reference has already been made. I propose, therefore, to place a brief outline of his experiments and views before the reader. Just before falling asleep, and immediately before becoming fully awake, many persons are subject to hallucinations partaking of many of the characteristics belonging to dreams. To them the name of hypnagogic (ῦπνος, _sleep_, and ἀγωγεύς, _leader_) hallucinations has been given, _i.e._ hallucinations which lead to sleep. Previous to M. Maury’s investigations, the phenomena in question had attracted some attention from German and French physiologists, but M. Maury’s investigations, many of which were performed upon himself, throw more light upon the subject than it has hitherto received. According to M. Maury, the persons who most frequently experience these hypnagogic hallucinations are those who are of an excitable constitution, and are generally predisposed to hypertrophy of the heart, pericarditis, and cerebral affections. This may be true, but in two most remarkable instances which have come under my observation, the type of organization was the very reverse of this.