al things. We may indeed not 'see' it
till some one points it out. But, if so, how does he point it out? By
his finger, and by describing its appearance,--by creating a premonitory
image of _where_ to look and of _what_ to expect to see. This
premonitory image is already an excitement of the same nerve-centres
that are to be concerned with the impression. The impression comes, and
excites them still further; and now the object enters the focus of the
field, consciousness being sustained both by impression and by
preliminary idea. But the maximum of attention to it is not yet reached.
Although we see it, we may not care for it; it may suggest nothing
important to us; and a rival stream of objects or of thoughts may
quickly take our mind away. If, however, our companion defines it in a
significant way, arouses in the mind a set of experiences to be
apprehended from it,--names it an enemy or as a messenger of important
tidings,--the residual and marginal ideas now aroused, so far from being
its rivals, become its associates and allies. They shoot together into
one system with it; they converge upon it; they keep it steadily in
focus; the mind attends to it with maximum power.

The attentive process, therefore, at its maximum may be physiologically
symbolized by a brain-cell played on in two ways, from without and from
within. Incoming currents from the periphery arouse it, and collateral
currents from the centres of memory and imagination re-enforce these.

In this process the incoming impression is the newer element; the ideas
which re-enforce and sustain it are among the older possessions of the
mind. And the maximum of attention may then be said to be found whenever
we have a systematic harmony or unification between the novel and the
old. It is an odd circumstance that neither the old nor the new, by
itself, is interesting: the absolutely old is insipid; the absolutely
new makes no appeal at all. The old _in_ the new is what claims the
attention,--the old with a slightly new turn. No one wants to hear a
lecture on a subject completely disconnected with his previous
knowledge, but we all like lectures on subjects of which we know a
little already, just as, in the fashions, every year must bring its
slight modification of last year's suit, but an abrupt jump from the
fashion of one decade into another would be distasteful to the eye.

The genius of the interesting teacher consists in sympathetic divination
of the sort