5. My collar bones are fastened to my shoulder blades and my breastbone;
they keep my arms from sliding too far forward.

6. The bones of old people are hard and brittle; those of children soft and
flexible; so I must sit and stand erect, that mine may not be bent out of
shape. I must not wear tight clothing, or do anything that will crowd them
out of their places.

7. My bones are made from my food, after it has been changed into blood; so
I must be careful to eat good, wholesome food, that they may be strong and
healthy.

8. I must not breathe impure air, because impure air makes bad blood, and
bad blood makes poor bones.

9. The body of every person is changing all the time, because the skin,
flesh, and bones are always wearing out, and the blood is always repairing
and building them again.

* * * * *

QUESTIONS FOR THE FORMULA.

1. Tell about the skull.

2. Tell about the spine.

3. Tell about the ribs.