repertory of sensation must be made familiar; more or less and very
guarded, watched and limited experiences of hunger, thirst, cold,
heat, tastes, sounds, smells, colors, brightnesses, tactile
irritations, and perhaps even occasional tickling and pain to play off
the vastly complex function of laughing, crying, etc., may in some
cases be judicious. Conscious and unconscious imitation or repetition
of every sort of copy may also help to establish the immediate and
low-level connection between afferent and efferent processes that
brings the organism into direct _rapport_ and harmony with the whole
world of sense. Perhaps the more rankly and independently they are
developed to full functional integrity, each in its season, if we only
knew that season, the better. Premature control by higher centers, or
cooerdination into higher compounds of habits and ordered serial
activities, is repressive and wasteful, and the mature will of which
they are components, or which must at least domesticate them, is
stronger and more forcible if this serial stage is not unduly
abridged.

But, secondly, many, if not most, of these activities when developed a
little, group after group, as they arise, must be controlled, checked,
and organized into higher and often more serial compounds. The
inhibiting functions are at first hard. In trying to sit still the
child sets its teeth, holds the breath, clenches its fists and perhaps
makes every muscle tense with a great effort that very soon exhausts.
This repressive function is probably not worked from special nervous
centers, nor can we speak with confidence of collisions with "sums of
arrest" in a sense analogous to that of Herbart, or of stimuli that
normally cause catabolic molecular processes in the cell, being
mysteriously diverted to produce increased instability or anabolic
lability in the sense of Wundt's _Mechanik der Nerven_. The concept