CHAPTER III
THE BRAIN AND NERVOUS SYSTEM
A fine brain, or a good mind. These terms are often used interchangeably, as if
they stood for the same thing. Yet the brain is material substance—so many cells
and fibers, a pulpy protoplasmic mass weighing some three pounds and shut
away from the outside world in a casket of bone. The mind is a spiritual thing—
the sum of the processes by which we think and feel and will, mastering our
world and accomplishing our destiny.
1. THE RELATIONS OF MIND AND BRAIN
Interaction of Mind and Brain.—How, then, come these two widely different
facts, mind and brain, to be so related in our speech? Why are the terms so
commonly interchanged?—It is because mind and brain are so vitally related in
their processes and so inseparably connected in their work. No movement of our
thought, no bit of sensation, no memory, no feeling, no act of decision but is
accompanied by its own particular activity in the cells of the brain. It is this that
the psychologist has in mind when he says, no psychosis without its
corresponding neurosis.
So far as our present existence is concerned, then, no mind ever works except
through some brain, and a brain without a mind becomes but a mass of dead
matter, so much clay. Mind and brain are perfectly adapted to each other. Nor is
this mere accident. For through the ages of man's past history each has grown up
and developed into its present state of efficiency by working in conjunction with
the other. Each has helped form the other and determine its qualities. Not only is
this true for the race in its evolution, but for every individual as he passes from
infancy to maturity.
The Brain as the Mind's Machine.—In the first chapter we saw that the brain
does not create the mind, but that the mind works through the brain. No one can
believe that the brain secretes mind as the liver secretes bile, or that it grinds it
out as a mill does flour. Indeed, just what their exact relation is has not yet been