Page:First steps in mental growth (1906).djvu/40

REFLEX HAND-MOVEMENTS

Reflex movements may be defined as those movements in which the excitation of an end organ is transmitted to a nerve center, and there directly and without conscious antecedents sets free an impulse which, through an outgoing nerve fibre, arouses activity in a muscle or other organ. Reflex movements are distinguished from spontaneous movements by the fact that they presuppose the existence of an external stimulus; and they are distinguished from instinctive movements by their greater simplicity—only a small number of muscles or other organs being involved in their production—and by the immediacy of the end they serve; and also by the absence of consciousness—particularly of characteristic moods or feeling-tones which arise in connection with instinctive actions.

The first note relating to reflex hand-movements which my record contains is with reference to clasping with the fingers. When J. was four hours old he firmly clasped a finger which was placed in the palm of his hand.^[1] On R.’s second day, when his cheek was lightly touched, his right hand made a quick and strong movement toward the face as if to remove the disturbance. A light touch of J.'s forehead while the child was asleep caused, on the second day, the arms to fly up convul-}}

1. In this first clasping, the thumb did not play a part, merely resting lightly against the second joint of the fore-finger. Clasping with the thumb contraposed, in the case of J., was established by the middle of his fourth month.