It is unquestionably of first interest to the psychologist to inquire not only why the child, at the early stage in which a choice of hands is manifested, should prefer the right hand for all strong movements; but also, whether previous experiences in the use of both hands leave behind a sense that the nervous discharge which actuated the right hand was stronger than that which actuated the left. But the point aimed at here is to ascertain the originating physical initiative of determinate action, antecedent to all memory; the precursor of any such action stimulated by memory of an efferent current of discharge of nervous force. For that end the following results, derived from a careful series of observations on the voluntary actions of a healthy child throughout its first year, are of practical significance and value. “(1) No trace of preference for either hand was found so long as there were no violent muscular exertions made (based on 2187 systematic experiments in cases of free movement of hands near the body: _i.e._ right hand 585 cases, left hand 568 cases: a difference of 17 cases; both hands 1034 cases; the difference of 17 cases being too slight to have meaning). “(2) Under the same conditions, the tendency to use both hands together was about double the tendency to use either (seen from the number of cases of the use of both hands in the statistics given above), the period covered being from the child’s sixth to her tenth month inclusive. “(3) A distinct preference for the right hand in violent efforts in reaching became noticeable in the seventh and eighth months. Experiments during the eighth month on this cue gave, in 80 cases, right hand 74 cases, left hand 5 cases, both hands 1 case. In many cases the left hand followed slowly upon the lead of the right. Under the stimulus of bright colours, from 86 cases, 84 were right-hand cases, and 2 left-hand. Right-handedness had accordingly developed under pressure of muscular effort. “(4) Up to this time the child had not learned to stand or to creep; hence the development of one hand more than the other is not due to differences in weight between the two longitudinal halves of the body. As she had not learned to speak, or to utter articulate sounds with much distinctness, we may say also that right or left-handedness may develop while the motor speech centre is not yet functioning.”[9] [9] _Science_, vol. xvi. pp. 247, 248.