Bone tied to a knot.
The acid has taken the lime from the other bone, so only the part which is not lime is left. You will be surprised to see how easily it will bend. You can twist it and tie it into a knot; but it will not easily break.
You have seen gristle in meat. This soft part of the bone is gristle.
Children's bones have more gristle than those of older people; so children's bones bend easily.
I know a lady who has one leg shorter than the other. This makes her lame, and she has to wear a boot with iron supports three or four inches high, in order to walk at all.
One day she told me how she became lame.
"I remember," she said, "when I was between three and four years old, sitting one day in my high chair at the table, and twisting one foot under the little step of the chair. The next morning I felt lame; but nobody could tell what was the matter. At last, the doctors found out that the trouble all came from that twist. It had gone too far to be cured. Before I had this boot, I could only walk with a crutch."
CARE OF THE SPINE.
Because the spine is made of little bones with cushions between them, it bends easily, and children sometimes bend it more than they ought.
If you lean over your book or your writing or any other work, the elastic cushions may get so pressed on the inner edge that they do not easily spring back into shape. In this way, you may grow round-shouldered or hump-backed.