"Give over,' says he, O Peter. What is it that you are doing? For those who are beginning to be possessed with a demon, or to be disturbed in their minds, begin in this way. They are first carried away by fancies to some pleasant and delightful things, then they are poured out in vain and fond motions towards things which have no existence. Now this happens from a certain disease of mind, by reason of which they see not the things which are, but long to bring to their sight those which are not. But thus it happens also to those who are suffering phrenzy, and seem to themselves to see many images, because their soul, being torn and withdrawn from its place by excess of cold or of heat, suffers a failure of its natural service. But those also who are in distress through thirst, when they fall asleep, seem to themselves to see rivers and fountains, and to drink; but this befalls them through being distressed by the dryness of the unmoistened body. Wherefore it is certain that this occurs through some ailment either of the soul or body.'