s--touch, taste, sight, hearing, smell--all depend on the nervous
system. Motion depends on it. A muscle can not contract without receiving
the stimulus from the nervous system. For example, if a nerve passing from
a nerve center to a muscle is severed, the particular muscle that is
supplied by the cut nerve is paralyzed.

The nervous system is often studied in two divisions--the cerebrospinal
division and the sympathetic division.

The cerebrospinal division consists of the brain and spinal cord, nerves,
and ganglia. The nerves of this division convey the impulses of motion and
sensation and supply all parts which are under the control of the will. For
example, the voluntary muscular tissue includes all the muscles which act
as the will directs. Another example: If anything comes in contact with any
part of the skin, the impression is immediately perceived. All the special
senses belong to this division.

The sympathetic division consists of nerves and ganglia. The muscular
tissue, which acts independently of the will--as, for example, the stomach,
intestines, womb, blood vessels, ducts, etc.--is called involuntary
muscular tissue, and receives nervous stimulus from the sympathetic
division.

The brain, spinal cord, and the ganglia are the central organs of the
nervous system. The nerves conduct the nervous influence. The nerves
terminate differently according to their function. The terminations are
called end organs. The terminal end organs in the skin and other parts
endowed with sensation receive the impressions, which are conveyed to the
brain, where they are appreciated. They are so sensitive that the most
gentle zephyr is perceived. They are so abundant that the point of the
finest needle can not pierce the skin without coming in contact with them,
and the sensation of pain is instantly conveyed to the brain. The terminal
end organs of the nerves that supply the muscles are different, as they
give the impulse which is conveyed by the motor nerves to the elements
which constitute the muscle, and this impulse is the excitation which
causes the muscle to contract. The terminal end organs of the special
senses of taste, smell, etc., receive their special impressions, and their
respective nerves carry the impressions to the brain.

There are two divisions of nerves, the afferent and efferent.

The afferent nerves are those which convey the impression to the nerve
centers. All the sensory nerves belong to this div