Phosphates : their chemical composition and uses in the different tissues of the body / by M.F. Anderson.
- Anderson, M. F. (Mark French)
- Date:
- 1877
Licence: Public Domain Mark
Credit: Phosphates : their chemical composition and uses in the different tissues of the body / by M.F. Anderson. Source: Wellcome Collection.
Provider: This material has been provided by The Royal College of Surgeons of England. The original may be consulted at The Royal College of Surgeons of England.
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![aucted. In the examination of the inorganic constituents of plant and animal tissue, especially for the detection of ]3hoS“- phates, care should be taken not to carry the incineration to any length; the material should only he charred sufficiently to carbonize the mass. If heat be continued for any length of time, so as to produce a white ash, a portion of the phos- phoric acid is volatilised, and a part reduced to phosphorus by the oxidation of the carbon in the tissue, at the expense of the phosphoric acid. The carbon seizes hold of the oxygen of phosphoric acid to form carbonic acid, and the phosphorus volatihses, and is treated as free phosphorus in the determina- tion. Besides this, long-continued heat produces other changes, and may even V(»latilise some portions of the bases. It is only in this way that I can explain the discrepancies that exist between the results of my investigations and such results as have up to the present time been received as representing the composition of the inorganic constituents of tissue. In Watts’ Dictionary of Chemistry (the best and most compendious work pubhshed on this science in the Enulish language) appears the following;—“In 100 parts of fresh brain, Breed found 0.027 parts of ash” (article nervous tissue), and then follows the per eentage composition of the ash. If the whole of the inorganic constituents of the brain only amount to 0.027 parts per cent.,^ there cannot possibly be *728 parts p>er cent, of phosphoric acid,- I should be inclined to regard the paragraph quoted as a misprint, but that I find the same discrepancies between my experiments, and those of others, to exist in many instances. I am led to the conclusion that the analysis of any organic compound for the determination of its mineral constituents should not be conducted by reducing the organic compound to ash, and that this method has led to great errors. A precipitate cam be readily made by using certain salts of phosphoric acid and the proper bases, which, on ignition, bears a close analogy to the phosphate found in tissues. A theoretical compound phosphate, consisting of Ca.O., Mg.O, Na.O, PO5, would eliow a per eentage composition of— Lime 17-28 Magnesia ... 19-80 Soda ■ 19-12 Phosphoric Acid ' .. .. .. .. .. 43-80 For comparison I have placed this by the side of twer precipitates made in my laboratory and analysed, and the](https://iiif.wellcomecollection.org/image/b2231605x_0015.jp2/full/800%2C/0/default.jpg)
