centers which have to do with clasping than of those concerned in standing.
Likewise the child's first attempts to feed himself or do any one of the thousand
little things about which he is so awkward, are partial failures not so much
because he has not had practice as because his nervous machinery connected
with those movements is not yet developed sufficiently to enable him to be
accurate. His brain is in a condition which Flechsig calls "unripe." How, then,
shall the undeveloped cells and system ripen? How shall the undeveloped cells
and fibers grow to full maturity and efficiency?
2. DEVELOPMENT OF NERVOUS SYSTEM THROUGH USE
Importance of Stimulus and Response.—Like all other tissues of the body, the
nerve cells and fibers are developed by judicious use. The sensory and
association centers require the constant stimulus of nerve currents running in
from the various end-organs, and the motor centers require the constant stimulus
of currents running from them out to the muscles. In other words, the conditions
upon which both motor and sensory development depend are: (1) A rich
environment of sights and sounds and tastes and smells, and everything else
which serves as proper stimulus to the sense organs, and to every form of
intellectual and social interest; and (2) no less important, an opportunity for the
freest and most complete forms of response and motor activity.