vements of the body.

The sensory nerves furnish the animal or man all knowledge of the
external world. The brain, sitting in absolute darkness, judges these
sensations, and sends out corresponding impulses to action. The
sensory nerves are the brain's sole teachers; the motor nerves, and
through them the muscles, are the brain's only servants. The untrained
brain learns its lessons poorly, and its commands are vacillating and
ineffective. In like manner, the brain which has been misued
[Transcriber's note: misused?], shows its defects in ill-chosen
actions--the actions against which Nature protests through her scourge
of misery. In this fact, that nerve alteration means ineffective
action, lying brain, and lying nerves, rests the great argument for
temperance, the great argument against all forms of nerve tampering,
from the coffee habit to the cataleptic "revival of religion."

The senses are intensely practical in their relation to life. The
processes of natural selection make and keep them so. Only those
phases of reality which our ancestors could render into action are
shown to us by our senses. If we can do nothing in any case, we know
nothing about it. The senses tell us essential truth about rocks and
trees, food and shelter, friends and enemies. They answer no problems
in chemistry. They tell us nothing about atom or molecule. They give
us no ultimate facts. Whatever is so small that we cannot handle it is
too small to be seen. Whatever is too distant to be reached is not
truthfully reported. The "X-rays" of light we cannot see, because our
ancestors could not deal with them. The sun and stars, the clouds and
the sky are not at all what they appear to be. The truthfulness of the
senses fails as the square of the distance increases. Were it not so,
we should be smothered by truth; we should be overwhelmed by the
multiplicity of our own sensations, and truthful response in action
would become impossible. Hyperaesthesia of any or all of the senses is
a source of confusion, not of strength. It is essentially a phase of
disease, and it shows itself in ineffectiveness, not in increased power.

Besides the actual sensations, the so-called realities, the brain
retains also the sensations which have been, and which are not wholly
lost. Memory-pictures crowd the mind, mingling with pictures which are
brought in afresh by the senses. The force of suggestion causes the
mental states or conditions of