~20.~ A person's height depends upon the length of his bones. The use of
alcohol and tobacco by a growing boy has a tendency to stunt the growth
of his bones, so that they do not develop as they should.


SUMMARY.

1. There are about two hundred bones in the body.

2. All together they are called the skeleton.

3. The skeleton is divided as follows:

_a._ The skull.

{ Ribs.
_b._ The trunk. { Breast-bone.
{ Pelvis.
{ Back-bone.
{ Collar-bone.
{ Shoulder-blade.

{ Upper arm-bones.
_c._ The arms. { Lower arm-bones.
{ Wrist.
{ Hand and fingers.

{ Thigh.
{ Knee-pan.