g a shoe, signing one's name, etc.,
conscious effort usually gives the first impulse to perform the act.
There may be cases, however, in which one finds himself engaged in some
customary act without any seeming initial conscious suggestion. This
would be noted, for instance, where a person starts for the customary
clothes closet, perhaps to obtain something from a pocket, and suddenly
finds himself hanging on a hook the coat he has unconsciously removed
from his shoulders. Here the initial movement for removing the coat may
have been suggested by the sight of the customary closet, or by the
movement involved in opening the closet door, these impressions being
closely co-ordinated through past experiences with those of removing the
coat. When, also, a woman is sewing or kneading bread, although she
seems to be able to give her attention fully to the conversation in
which she may be engaged, yet no doubt a slight trace of conscious
control is still exercised over the other movements. This is seen in the
fact that, whenever the conversation becomes so absorbing that it takes
a very strong hold on the attention, the habitual movements may cease
without the person being at first aware that she has ceased working.

=Habit and Nervous Action.=--The general flow of the nervous energy
during such processes as the above, in which there is an interchange
between conscious and habitual control, may be illustrated by the
following figures. In these figures the heavy lines indicate the process
actually going on, while the broken lines indicate that although such
nerve courses are established, they are not being brought into active
operation in the particular case.

[Illustration: FIG. 1, FIG. 2, FIG. 3

A. Sensory Stimulus
B. Lower Sensory Centre
C. Higher Sensory Centre

A' Higher Motor Centre
B' Lower Motor Centre
C' Motor Response]

The arrows in Figure 1 indicate the course of sensory stimulation and
motor response during the first efforts to acquire skill in any
movement. No connections are yet set up between lower centres and the
acts are under conscious control.

The arrows in Figure 2 indicate the course of sensory stimulus and motor
response in an ordinary habitual act, as when an expert fingers the
piano keys or controls a bicycle while his mind is occupied with other
matters.

The arrows in Figure 3 indicate how, even in performing what is
ordinarily an habitual act, the mind may at any time assume control of
t