COOPERATIONThis nervous system is dual. One system, known as the
sympathetic, is the channel for all those activities which are
not consciously directed by our volition, such as the operation
of the digestive organs, the repair of the daily wear and tear
of the tissues, and the like.
The other system, known as the voluntary or cerebro-spinal
system, is the channel through which we receive conscious per-
ception from the physical senses and exercise control over the
movements of the body. This system has its center in the brain,
while the other has its center in the ganglionic mass at the
back of the stomach known as the solar plexus, and sometimes
spoken of as the abdominal brain. The cerebro-spinal system is
the channel of our volitional or conscious mental action, and
the sympathetic system is the channel of that mental action
which unconsciously supports the vital functions of the body.
Thus the cerebro-spinal system is the organ of the conscious
mind and the sympathetic is that of the subconscious mind.
But the interaction of conscious and subconscious minds
requires a similar interaction between the corresponding sys-
tems of nerves, and one conspicuous connection by which
this is provided is the "vagus" nerve. This nerve passes out of
the cerebral region as a portion of the voluntary system, and
through it we control the vocal organs; then it passes onward
to the thorax, sending out branches to the heart and lungs;
and finally, passing through the diaphragm, it loses the outer
coating which distinguishes the nerves of the voluntary system
and becomes identified with those of the sympathetic system,
so forming a connecting link between the two and making the
man physically a single entity.
Similarly different areas of the brain indicate their connec-
tion with the objective and subjective activities of the mind
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