Читать книгу The House We Live In; or, The Making of the Body онлайн

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You must not think that live bones look like one which has been lying out-of-doors a long time. Live bones are full of blood and have a pinkish color. They also have an outside skin, which can be peeled off, as you see in this picture.

A bone with the outside skin partly peeled off.

Amy: What are the bones made of?

End of a bone sawed open.

Mother: Of animal and earthy matter. You can take the animal matter out of a bone by burning it in the fire. It will then be white and brittle. If you soak a bone in a kind of acid, the earthy matter will come out, and it will then be so soft you can tie it in a knot like this. When children are very young, their bones are soft and easily bent. This is because there is more animal than earthy matter. Children sometimes get hard falls, and their bones bend but do not break. Some, when very young, have legs that are bent like a bow. This is caused by standing and walking before the bones are strong enough to bear the weight of the body, or by disease.