ll and will prepare the way for success in life later.
Nobody wants a grumbling clerk or a sour-faced housekeeper.

[Illustration: FIG. 88.--The difference in appearance between a
pouting and a pleasant expression.]

=Parts of the Body work without Orders from the Brain.=--A snake with
its brain crushed will still squirm and a chicken with its head cut
off jumps about. These movements are caused by orders sent from the
spinal cord. When the hand or foot is being hurt, the spinal cord
orders the muscles to draw the limb away even before we feel the pain
in the brain. Many of the movements of the body which are often
repeated may be directed by the spinal cord, while the brain is left
free to do other work. This is why the spinal cord is called the
helping manager.

The action of the muscles in the walls of the blood vessels, the
working of the stomach, the liver, pancreas, and other glands are not
directed by the brain, but by the _sympathetic nerves_. These extend
from a little cord on either side of the backbone to all parts of the
body and make the organs, such as the heart and sweat glands, which we
cannot make obey our will, do their work.

=Injury to the Nerves.=--The nerves are so important for the welfare
of the body that all the chief ones are placed deep in the flesh,
where they are not likely to be hurt. If the nerves leading to the arm
were cut, it could not be moved, and we should have no feeling in it.
The hurting of a part of the brain, the spinal cord, or the nerves may
cause loss of feeling or motion in the leg, arm, or other part of the
body. Such a part then seems asleep or dead and is said to have
_paralysis_.

Pressing on a nerve prevents it from acting. Sitting so as to press on
the nerve of the leg often makes the foot go to sleep. The bursting of
a blood vessel in the brain may let a blood clot form and press on the
nerves which govern the arm or the leg. This pressure may cause
paralysis.

=Resting the Brain.=--When there is no food in the stomach, it has
time to rest. When we sit down or lie down, the muscles get rest. The
brain is always busy except when we are asleep. No one can live even a
week without sleep. If a dog is kept awake five days, it will die.

[Illustration: FIG. 89.--Sleeping in the position shown in the lower
figure prevents free breathing and tends to cause round shoulders. The
upper figure shows correct position.]

Children need much more sleep than older persons. M