and
grow, and it tells the heart and arteries how much blood to send to
each cell. If we had to think about feeding an arm or a leg, we should
sometimes forget it, but the spinal cord keeps doing it without our
thinking of it. We put food into the body, and the spinal cord tells
the cells to use it. If it stops acting for an instant, the cells stop
work and we die. We cannot change its action by any amount of thinking.

[Illustration: =Regions of the head and action of the different parts
of the brain.=]

=140. The brain.=--The nerves of the body go to the brain as well as
to the spinal cord. The brain lies in the top of the head. A hard
cover of bone keeps it from getting hurt. It is a soft white mass, and
weighs about three pounds. Its outside is made of cells, while its
inside is the very beginning of the nerves of the body.

=141. The mind.=--The mind is the real man. It is the thinking part of
himself. It lives in the body and works by means of the cells of the
brain. If these cells are hurt or killed, the body seems to have no
mind, but yet it may keep on living. If all the mind leaves the body,
the body is dead.

By means of the mind we feel, and know, and think. The mind uses each
part of the brain for only one kind of work.

=142. The senses.=--The cells of the body send word to the brain over
the nerves. The eye tells of sight, the ear of sounds, the nose of
odors, the mouth of tastes, and the skin of feelings. All these
messages go to the back part of the brain. They tell the mind of the
news outside of the body. We get all our knowledge in this way. The
cells also tell of their need of food and drink by means of the
feelings of hunger and thirst.

=143. Motion.=--The mind in the cells of the top part of the head
sends the orders for moving the different parts of the body. When we
wish to run, the mind in the top of our head sends an order over our
nerves to our legs, and they carry the body where we wish. If the top
part of your brain is hurt, as by a blow, it cannot send orders to
move, but you will lie stunned.

=144. Memory.=--The mind lays away all its messages, and often looks
them over again. These old messages are called _memories_. They always
stay with the brain, and the mind can call them up at any time. Our
memories make our knowledge.

Every act of the mind leaves some mark on the memory. We may not be
able to bring it back when we want to, but it will come back some
time. Every bad wo