An elementary text-book of physiology / by Vincent T. Murché.

  • Murché, Vincent T. (Vincent Thomas)
Date:
[between 1880 and 1889?]
Catalogue details

Licence: Public Domain Mark

Credit: An elementary text-book of physiology / by Vincent T. Murché. Source: Wellcome Collection.

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    bones have to do most of the work in moving the body. Hence we find them surrounded so thickly with flesh that we cannot see the shape of them. The flesh, as you will learn by and by, has to do the work of moving the bones one upon another. Hence, where much work has to be done, there we find the greatest amount of flesh or muscle. Bone Tissue. Bone consists partly of animal matter and partly of earthy or mineral matter. In infancy there is a much smaller proportion of earthy matter in bone than at a more mature period of life, and the bones are at this age less rigid. This explains why it is so easy to bend or twist a young child’s bones out of shape. You have all seen a child bow-legged or bandy. The child was not born like that, but bad nursing and allowing him, too soon, to stand on his feet have bent the soft yielding substance which in time is to become firm bone. In adult age human bone contains about one-third its weight of animal matter and two-thirds mineral matter (chiefly phos- phate of lime). The effect of this mineral matter is to harden the bones. As we advance in years the bones become still more deeply impregnated with these earthy matters, and in old age they thus become very brittle. Hence in elderly persons a slight slip will often cause a broken limb, and it is then a very difficult matter to get the bone to reunite firmly. A child you see is not likely to break its bones by a fall because they are too flexible, and rather become twisted out of shape, while an old man’s bones are brittle, and will easily snap. Two simple experiments will prove to you the composition of bone:— 1. Place a bone on a bright red fire, and let it remain there and burn for some time. When you take it out you will find that it is lighter—indeed that it has lost about one-third of its weight. All the animal matter has been burned away, and what remains is the mineral or earthy matter. If you drop this on the stones it will break into pieces. 2. Place another bone in some dilute muriatic acid, and let it remain in the acid for a few weeks. (This acid is often called
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