f vertebrata, to
be presently described, g.c., g.c. are ganglion cells; they may have
many hair-like processes, usually running into continuity with
the axis cylinders of nerve fibres, in which case they are called
multi-polar cells, or they may be uni- or bi-polar.

Section 104. The simplest example of the action of the nervous
system is reflex action. For instance, when the foot of a frog, or the
hand of a soundly sleeping person, is tickled very gently, the limb is
moved away from the irritation, without any mental action, and entirely
without will being exercised. And when we go from light into darkness,
the pupil of the eye enlarges, without any direct consciousness of the
change of its shape on our part. Similarly, the presence or food in the
pharynx initiates a series of movements-- swallowing, the digestive
movements, and so on-- which in health are entirely beyond our
mental scope.

Section 105. A vast amount of our activities are reflex, and in such
action an efferent stimulus follows an afferent promptly and quite
mechanically. It is only where efferent stimuli do not immediately
become entirely transmuted into outwardly moving impulses that
mental action comes in and an animal feels. There appears to be a
direct relation between sensation and motion. For instance, the
shrieks and other instinctive violent motions produced by pain,
"shunt off" a certain amount of nervous impression that would
otherwise register itself as additional painful sensation. Similarly most
women and children understand the comfort of a "good cry," and its
benefit in shifting off a disagreeable mental state.

Section 106. The mind receives and stores impressions, and these
accumulated experiences are the basis of memory, comparison,
imagination, thought, and apparently spontaneous will. Voluntary
actions differ from reflex by the interposition of this previously stored
factor. For instance, when a frog sees a small object in front of him,
that may or may not be an edible insect, the direct visual impression
does not directly determine his subsequent action. It revives a number
of previous experiences, an image already stored of similar insects
and associated with painful or pleasurable gustatory experiences.
With these arise an emotional effect of desire or repulsion which,
passes into action of capture or the reverse.

Section 107. Voluntary actions may, by constant repetition, become
quasi-reflex in character. The intel