The same kind of curiosity which impels the astronomer, the biologist, and the sociologist to search out the primitive forms in their respective fields, prompts also to the study of the ways of infancy; particularly, to the effort to bring to light the germinal processes from which spring the characteristic activities of the developed mind. Accordingly, we have witnessed, in comparatively recent years, the rise of a wide-spread interest in the psychology of infancy. A few investigators, notably Darwin, have been attracted to the study of the infant mind through reflection on the physical and mental relations of man to the lower animals. Preyer began his study of the child, as he says in his preface, "from the physiological point of view, with the object of arriving at an explanation of the origin of the separate vital processes." Later, Preyer divided his work into three parts: (1) life in the embryo, (2) the physical development of the newly born and the very young child, (3) mental development in infancy and early childhood. Preyer's interest, at first, was in the phenomena of physical development, and his work, Die Seele des Kindes, though rich in the data of child psychology, has—from the psychological point of view—the defects of a work written by one who was physiologist rather than psychologist.
A larger number of students of infancy and early childhood have been interested primarily in the phenomena of
