length and he will
become dwarfed or deformed.

SUMMARY.

1. To keep the bones healthy they must have plenty of healthful food.

2. The whole-grain preparations furnish the best food for the bones.

3. Walking at too early an age often makes the legs crooked.

4. Hard work at too early an age stunts the growth.

5. Bad positions and tight or poorly-fitting clothing are common causes
of flat chests, round shoulders, and other deformities.

6. Tight or high-heeled shoes deform the feet and make the gait awkward.

7. The bones may be easily broken or put out of joint, or the ligaments
may be torn by rough play.

8. Alcohol prevents healthy growth.

CHAPTER XX.

THE MUSCLES AND HOW WE USE THEM.

~1. The Muscles.~--Where do people obtain the beefsteak and the
mutton-chops which they eat for breakfast? From the butcher, you will
say; and the butcher gets them from the sheep and cattle which he kills.
If you will clasp your arm you will notice that the bones are covered by
a soft substance, the flesh. When the skin of an animal has been taken
off, we can see that some of the flesh is white or yellow and some of it
is red. The white or yellow flesh is fat. The red flesh is lean meat,
and it is composed of muscles.

~2. The Number of Muscles.~--We have about five hundred different
muscles in the body. They are arranged in such a way as to cover the
bones and make the body round and beautiful. They are of different forms
and sizes.

~3.~ With a very few exceptions the muscles are arranged in pairs; that
is, we have two alike of each form and size, one for each side of the
body.

~4. How a Muscle is Formed.~--If you will examine a piece of corned or
salted beef which has been well boiled, you will notice that it seems to
be made up of bundles of small fibres or threads of flesh. With a little
care you can pick one of the small fibres into fine threads. Now, if you
look at one of these under a microscope you find that it is made of
still finer fibres, which are much smaller than the threads of a
spider's web. One of these smallest threads is called a _muscular
fibre_. Many thousands of muscular fibres are required to make a muscle.

[Illustration: MUSCULAR FIBRES.]

~5.~ Most of the muscles are made fast to the bones. Generally, one end
is attached to one bone, and the other to another bone. Sometimes one
end is made fast to a bone and the other to the skin or to other
muscles.

~6. The Tendons.~-