When left to themselves children continue the joys of sociability by means of an imaginary playmate. Although all must have noticed this who have observed children at all, only close and constant observation will enable one to realize the extent to which it is carried on. It is not an occasional practice, but, rather, a necessary form of thought, flowing from a life in which personal communication is the chief interest and social feeling the stream in which, like boats on a river, most other feelings float. Some children appear to live in personal imaginations almost from the first month; others occupy their minds in early infancy mostly with solitary experiments upon blocks, cards, and other impersonal objects, and their thoughts are doubtless filled with the images of these. But, in either case, after a child learns to talk and the social world in all its wonder and provocation opens on his mind, it floods his imagination so that all his thoughts are conversations. He is never alone. Sometimes the inaudible interlocutor is recognizable as the image of a tangible playmate, sometimes he appears to be purely imaginary. Of course each child has his own peculiarities. R., beginning when about three years of age, almost invariably talked aloud while he was playing alone—which, as he was a first child, was very often the case. Most commonly he would use no form of address but “you,” and perhaps had no definite person in mind. To listen to him was like hearing one at the telephone; though occasionally he would give both sides of the conversation. At times again he would be calling upon some real name, Esyllt or Dorothy, or upon “Piggy,” a fanciful person of his own invention. Every thought seemed to be spoken out. If his mother called him he would say, “I’ve got to go in now.” Once when he slipped down on the floor he was heard to say, “Did you tumble down? No. _I_ did.”