Another mystery lay in dreams, which have been connected with supersensual powers all the world over. To the savage who cannot analyse his experience the dream-world is as real as that of his waking hours. The dreams that follow fasts, whether compulsory through deficient food, or voluntary through preparation for some solemn event, possess peculiar vividness; and, when attention has been fixed upon some expected crisis, readily acquire a prophetic significance. Divine forms are seen, and strange intimations are conveyed from another world. The dream verses of the Icelander brought tidings from those who had been lost at sea. To sleep upon the grave of a dead kinsman, still more of a hero or a seer, was the means of receiving communications from the wisdom of the dead. Did not philosophy teach that in sleep the mind is less hampered by its physical environment, and attains truth more nearly; {180} and what condition was so suitable, therefore, for the beneficent revelation of a god? In Greece, accordingly, the practice of sleeping at the tombs of heroes or in the temples of gods was regularly organised. The sanctuaries of Æsculapius, of which more than two hundred can be traced round the Eastern Mediterranean and in Italy, were specially frequented by patients who resorted thither for medical treatment and the advice of the god. The sufferer must pass through the preliminary discipline of the bath, and to his purifications must add the due offering of a sheep. The victim's fleece was carried into the holy precincts, and on it the sick man lay down for the night. In the visions of the dark hours the god appeared, and prescribed the mode of cure, or even condescended to operate himself. An inscription at Epidaurus records that the stiffened fingers of a patient were straightened out and restored for use by the god's own grasp. Was it surprising that Æsculapius should become the object of increasing reverence, and in the second century of our era should be enthroned in the highest as "Saviour (or Preserver) of the universe"?