that it could stand alone, or without assistance. The walking movements which are performed by a child much too young to walk, when it is held so that its feet touch the ground, are classified by Preyer as instinctive. The time at which walking proper begins varies much with different children, the limits being from eight to sixteen months. When a child which is beginning to walk falls, it throws its arms forward to break the fall; this action must be instinctive. In the twenty-fourth month Preyer's child began spontaneously to dance to music and to beat time correctly. A chapter is devoted to imitative movements. At the end of the fifteenth week the child would imitate the movement of protruding the lips, at nine months would cry on hearing other children do so, and at twelve months used to perform in its sleep imitative movements which had made a strong impression while awake--e.g., blowing; this shows that dreaming occurs at least as early as the first year. After the first year imitative movements are more readily learned than before. Shaking the head as a sign of negation was found by Preyer, as by other observers, to be instinctive, and he adopts Darwin's explanation of the fact--viz., that the satisfied suckling in refusing the breast must needs move its head from side to side. In the seventeenth month the child exhibited a definite act of intelligent adjustment, for, desiring to reach a toy down from a press, it drew a traveling-bag from another part of the room to stand upon. We mention this incident because it exhibits the same level of mental development as that of Cuvier's orang, which, on desiring to reach an object off a high shelf, drew a chair below the shelf to stand upon. Anger was expressed in the tenth month, shame and pride in the nineteenth. Between the tenth and eleventh month the first perception of causality was observed. Thus on the three hundred and nineteenth day the child was beating on a plate with a spoon and accidentally found that the sound was damped by placing the other hand upon the plate; it then changed its hands and repeated the experiment. Similarly at eleven months it struck a spoon upon a newspaper, and changed hands to see if this would modify the sound. In some children, however, the perception of causality to this extent occurs earlier. The present writer has seen a boy when exactly eight months old deriving much pleasure from striking the keys of a piano, and clearly showing that he understood the action of striking the keys to be the antecedent required for the production of the sound.