cal concomitant of "accommodation" in the organs of sense;
an accommodation, physiologically incomplete in the young child, which
requires to develop itself according to Nature. An object not adapted
to become a useful stimulus to the powers of accommodation in process
of development would not only be incapable of sustaining attention as
a psychical fact, but would also, as a physiological fact, weary or
actually injure the organs of accommodation such as the eye and ear.
But the child who _chooses_ the objects, and perseveres in their use
with the utmost intensity of attention, as shown in the muscular
contractions which give mimetic expression to his face, evidently
experiences _pleasure_, and pleasure is an indication of healthy
functional activity; it always accompanies exercises which are useful
to the organs of the body.

Attention also requires a _preparation_ of the ideative centers in
relation to the external object for which it is to be demanded: in
other words, an internal, psychical "adaptation." The cerebral centers
should be excited in their turn by an internal process, when an
external stimulus acts. Thus, for instance, any one who is expecting a
person, sees him arriving from a considerable distance; not only
because the person presents himself to the senses, but because he was
"expected." The distant figure claimed attention because the cerebral
centers were already excited to that end. By means of similar
activities a hunter is conscious of the slightest sound made by game
in woods. In short, two forces act upon the cerebral cell, as upon a
closed door: the external sensory force which knocks, and the internal
force which says: Open. If the internal force does not open, it is in
vain that the external stimulus knocks at the door. And then the
strongest stimuli may pass unheeded. The absent-minded man may step
into a chasm. The man who is absorbed in a task may be deaf to a band
playing in the street.

The central action that constitutes attention is the factor of the
greatest psychological and philosophic value, and the one which has
always represented the maximum among the practical values in pedagogy.
The whole art of teachers has consisted, in substance, in preparing
the attention of the child to make it _expectant_ of their
instruction, and in securing the cooperation of those internal forces
which should "open the door" when they "knock." And as the thing which
is quite unknown, or that which is