A treatise on the human skeleton (including the joints) / by George Murray Humphry.
- George Murray Humphry
- Date:
- 1858
Licence: Public Domain Mark
Credit: A treatise on the human skeleton (including the joints) / by George Murray Humphry. Source: Wellcome Collection.
Provider: This material has been provided by the Francis A. Countway Library of Medicine, through the Medical Heritage Library. The original may be consulted at the Francis A. Countway Library of Medicine, Harvard Medical School.
15/754 page 3
![skeleton, but only in veiy limited portions; according to Tomes and De Morgan it occurs in the petrous portion of tlie temporal bone\ Earthy eonsti- '^^^® pliospliate of lime, wliicli forms tlie chief part tuents. Qf ii^g mineral constituents, is sometimes called bone- earth pliosphate, being rather a peculiar salt. It is regarded as a tribasic phosphate, consisting of 8 equivalents of lime, 1 of water, and 3 of phosphoric acid. The great predominance of this salt over the carbonate is a striking feature in the composition of bone, as compared with that of shell, in which the phosphate is either absent altogether, or exists only in very small quantities. The carbonate is a simpler salt, much more abundant in the inorganic world, and answers the purpose of the earthy material of shell sufficiently well, being in it united with only a small quantity of animal matter. But in true bone, the greater proportion of animal substance ren- dered necessary for the purposes of growth, &c. requires the sub- stitution of the pliosphate, which is capable of forming a harder compound with animal substance than the carbonate. In the hardest part of the skeleton—the enamel of the teeth—it is present in still greater quantity, forming more than 80 per cent. It possesses the same property as the animal matter of preserving its characters and composition for a great length of time, having been found unaltered in fossil bones. The salts of phosphorus exist in small quantities in the inorganic world, but form a very important ingredient in some vegetables, particularly those vegetables which are most nutritious, such as bread-corn, &c. Hence bone-powder is so valuable an article of manure. ,, , , The union of the animal and the earthy constituents Modes of com- ■/ bination. gf ]3one is evidently very intimate, though the precise nature of it is not well understood. The variable proportions in which they are combined to form bone, and the facility with which they can be separated, or partially separated, without destroying the shape of the bone, proves that if it be a chemical union, it is not quite of the ordinary kind. 1 Quain's Anatomy, 1856, i. p. cxxvi.](https://iiif.wellcomecollection.org/image/b21060058_0015.jp2/full/800%2C/0/default.jpg)
