THE first case here reported came to the notice of the writer through the attending physician; the second case was reported by the father of the child after the attending physician had failed of satisfactory treatment. The second case is especially interesting and serviceable in connection with the phenomenon of visual space perception. The first case is that of a boy, nine years of age, healthy, vigorous, who in his play ground and street reactions parallels that of any normal boy of his age. Aside from measles and an occasional disturbance of digestion he has been singularly free from childhood's common diseases. The father and mother are strong Hanoverian Germans holding with puritanic strictness to the dogmas of the Lutheran religious faith. So far as is ascertainable there can be no question of faulty inheritance, at least not so far as the immediate parents and grandparents enter into the problem. The child upon retiring and usually while still wide awake uttered wild screams of terror. Upon inquiry the child complained of falling and clutched vigorously to the bed clothes and the arms of the parents. Usually the phenomenon disappeared when he was taken out of bed and walked about but reappeared when he lay down. He complained of pain in his eyes, neck and fore- and after-parts of his head. No amount of persuasion dispelled the illusion. It should be emphasized that the illusion occurred in full waking state and rarely as a dream. An attempt was made to correlate the illusion with the momentum of the day's activity. According to the parents the illusion appeared in aggravated form when the neighborhood boys congregated in a cluster of trees at the edge of the village and when playing "train" in which case the barn-top functioned as the locomotive while a high board fence and an adjoining neighbor's barn functioned as the cars and caboose respectively. The village physician offered no explanation. He prescribed a hot bath and a "closer supervision of the evening meal." The dilatation of the cutaneous capillaries consequent to the bath lowered the cerebral circulation and to some extent reduced the intensity of the illusion.