ges 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 settled. Yet it is
easy to see that if the mind must use the brain as a machine and work
through it, then the mind must be subject to the limitations of its
machine, or, in other words, the mind cannot be better than the brain
through which it operates. A brain and nervous system that are poorly
developed or insufficiently nourished mean low grade of efficiency in
our mental processes, just as a poorly constructed or wrongly adjusted
motor means loss of power in applying the electric current to its work.
We will, then, look upon the mind and the brain as counterparts of each
other, each performing activities which correspond to activities in the
other, both inextricably bound together at least so far as this life is
concerned, and each getting its significance by its union with the
other. This view will lend interest to a brief study of the brain and
nervous system.

2. THE MIND'S DEPENDENCE ON THE EXTERNAL WORLD

But can we first see how in a general way the brain and nervous system
are primarily related to our thinking? Let us go back to the beginning
and consider the babe when it first opens its eyes on the scenes of its
new existence. What is in its mind? What does it think about? Nothing.
Imagine, if you can, a person born blind and deaf, and without the sense
of touch, taste, or smell. Let such a person live on for a year, for
five years, for a lifetime. What would he know? What ray of intelligence
would enter his mind? What would he think about? All would be dark to
his eyes, all silent to his ears, all tasteless to his mouth, all
odorless to his nostrils, all touchless to his skin. His mind would be a
blank. He would have no mind. He could not get started to think. He
could not get started to act. He would belong to a lower scale of life
than the tiny animal that floats with t