Thomson's Conspectus of the British pharmacopoeias.

  • Anthony Todd Thomson
Date:
1852
Catalogue details

Licence: Public Domain Mark

Credit: Thomson's Conspectus of the British pharmacopoeias. Source: Wellcome Collection.

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    not only highly inflamed, but ulcerated. The lungs are sometimes black and turgid with blood; the mitral and tricuspid valves of the heart are covered with red patches, and these extend to the fleshy columns ; but the chief morbid appearances are to be looked for in the stomach and intestines. The contents of the former of these, and of portions of the latter, ought in every case to be carefully preserved, and washed in tepid distilled water. Cases have proved fatal in which no morbid changes have been detected. Tests. If any solid particles be found in the stomach, throw a few of them upon red hot coals, they will be decomposed and exhale allia- ceous vapour: or, mix one part of them with three parts of a mixture, consisting of one part of finely powdered charcoal, and two parts of very dry carbonate of potassa; put this into a small glass tube, the upper inner surface or empty part of which is kept clean, whilst the powder is introduced, by being previously lined with paper. Having withdrawn the paper, stop the open end loosely with a little tow, or a piece of soft paper; then place the closed end for a few minutes in the flame of a spirit lamp until it becomes incandescent; when, if arsenious acid be present, a brilliant metallic crust will be found lining the upper part of the tube. This crust, placed on hot coals, will exhale dense white fumes and a strong smell of garlic. If no solid particles be found, boil the contents of the stomach with liquor potassae, and strain through a piece of linen rag; divide the fluid into different portions, test each portion separately by the fol- lowing reagents:— 1. Put one portion into Marsh's apparatus for the formation of arse- niuretted hydrogen gas, with some diluted sulphuric acid and a piece of pure zinc, and inflame the gas evolved at the jet. If arsenious acid be present, a piece of glass held over the flame will display a spot of metallic arsenic, surrounded by a circle of black oxide of arsenic, which is surrounded by a second circle of arsenious acid ; or pass the arse- niuretted hydrogen gas through a bent tube, and heat it, at a point a few inches from the jet, in the flame of a spirit lamp ; a crust of metallic arsenic will line the tube on the farther side of the heated point A modification of Marsh's apparatus has been recommended by a com- mission lately appointed by the Prussian government, the object of, which is to ascertain the weight of the arsenic present. Or acidulate the fluid to be tested with hydrochloric acid, and boifc stripes of clean metallic copper in it: if arsenious acid be present, a coating of metallic arsenic will cover the copper. (Reinseh.) The grains picked out of the stomach may be tested in the same manner. This test is decisive, but it requires to be used in the following manner, if the contents of the stomach contain much fatty matter. Take a bell glass, open at the top, and furnished with a stop cock and glass jet; fill it with hydrogen gas; place it in a jar containing the contents, of the stomach strained, and the washing of the stomach, and some diluted sulphuric acid and pure zinc. Open the stop cock until the fluid rises considerably into the bell glass; then close the stop cock; but, after the gas has been extricated and the fluid has descended,, open it again, inflame the gas at the jet and use it in the same manner as Mr. Marsh's instrument. A better mode is the modification of Marsh's apparatus proposed by the Author.. (See Pharmaceutical Trans, by T. Bell, p. 92.) 2. Drop, into the second portion, a solution of nitrate of silver to excess, in order to precipitate all the hydrochlorates it may contain; then, after the fluid has become clear, touch the surface with a glass rod dipped in liquid ammonia. If arsenious acid be present, a yellow arsenite of silver will fall from the point of the rod. 3. Drop into a third portion some ammoniated sulphate of copper: if arsenious acid be present, Scheele's green will be formed. The ac- cordance of these tests affords sufficient evidence. The tubes, and the glass coated with the metallic arsenic, should be taken into court, as
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