Читать книгу A Practical Physiology: A Text-Book for Higher Schools - Albert F. Blaisdell - Страница 13

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Experiment 11. Take a portion of the decalcified bone obtained from Experiment 4, and wash it thoroughly in water: in this it is insoluble. Place it in a solution of carbonate of soda and wash it again. Boil it in water, and from it gelatine will be obtained.

Experiment 12. Dissolve in hydrochloric acid a small piece of the powdered bone-ash obtained from Experiment 3. Bubbles of carbon dioxid are given off, indicating the presence of a carbonate. Dilute the solution; add an excess of ammonia, and we find a white precipitate of the phosphate of lime and of magnesia.

Experiment 13. Filter the solution in the preceding experiment, and to the filtrate add oxalate of ammonia. The result is a white precipitate of the oxalate of lime, showing there is lime present, but not as a phosphate.

Experiment 14. To the solution of mineral matters obtained from Experiment 3, add acetate of soda until free acetic acid is present, recognized by the smell (like dilute vinegar); then add oxalate of ammonia. The result will be a copious white precipitate of lime salts.

Experiment 15. To show how the cancellous structure of bone is able to support a great deal of weight. Have the market-man saw out a cubic inch from the cancellous tissue of a fresh beef bone and place it on a table with its principal layers upright. Balance a heavy book upon it, and then gradually place upon it various articles and note how many pounds it will support before giving way.

Experiment 16. Repeat the last experiment, using a cube of the decalcified bone obtained from Experiment 4.

[Note. As the succeeding chapters are studied, additional experiments on bones and their relation to other parts of the body, will readily suggest themselves to the ingenious instructor or the thoughtful student. Such experiments may be utilized for review or other exercises.]