Principles of forensic medicine / by William A. Guy and David Ferrier.

Date:
1888
Catalogue details

Licence: Public Domain Mark

Credit: Principles of forensic medicine / by William A. Guy and David Ferrier. Source: Wellcome Collection.

Provider: This material has been provided by the Royal College of Physicians of Edinburgh. The original may be consulted at the Royal College of Physicians of Edinburgh.

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    STllYCHNINE. crystals in fig. 114 are either regular octahedra, or modifications of tlac same or short six-sided prisms; and there are one or two dodecahedra, rhomboidal and pentagonal, as well as plates of aitterent forms, and among them one of the deep triangular plates so common m some specimens of arsenious acid. Strychnine has an intensely bitter and very persistent taste, stated to be distinctly perceptible in solutions containing one grain of the alkaloid in a gallon (70,000 grains) of water. Strychnine is so insoluble m water as to require for its solution upwards of 7000 times its weight, at 50° (one grain in about fourteen measured ounces), and 2500 times its weight at 212°. Wormley gives, as the result of many experiments, one in 8333 parts of water. But it is more or less soluble in ether, alcohol, amylic alcohol, benzene, and chloroform. It is soluble in about 1000 parts of commercial ether, 200 of absolute alcohol, 120 of amylic alcohol, 250 of benzene, and 8 of chloroform. If pure, the strong mineral acids do not colour it; but when it contains brucine, nitric acid more or less reddens it. When heated on porcelain, it melts slowly into a dark brown liquid, smokes abundantly, gives out an agreeable odour, and deposits a moderately abundant carbon. Tests.—a. The form of the crystals as above described, h. The intensely bitter taste, c. The very sparing solubility in water. d. The negative effect of strong sulphuric acid. Strychnine belongs to the group of alkaloids which are not changed in colour by cold sulphuric acid. Nor is any colour developed when the acid solution is warmed, and only a light yellow tint when it is heated, e. The chemical and galvanic colour tests. /. The test of sublimation. The colour tests.—1. Chemical colour tests, a. Place the smallest visible crystal or granule of strychnine on white porcelain or enamelled glass. Add a drop of pure strong sulphuric acid, and mix the acid and alkaloid thoroughly with a glass spatula. No change of colour takes place; or, if it contain brucine, a faint rose tint. Near this acid mixture place a speck of bichromate of potas- sium, and then bring the liquid and the reagent together with the point of the spatula, having previously placed the porcelain in a favourable light. At the point of contact a deep rich blue colour makes its appearance, and on stirring the reagent into the acid solution, extends through the whole liquid, which soon changes to purple, from purple to crimson, from crimson to a rich red brown, and then gradually fades into a bright red, which colour it retains for several hours, h. Proceed in the same manner with ferridcyanide of potassium, c. Proceed in the same way with the permanganate of potassium, cl. Place a drop of strong sulphuric acid on the white porcelain; add a minute fragment of the peroxide of man- ganese (not more than will impart to the acid when mixed with it a neutral tint). Draw out a thin line of this acid liquid with the point of the spatula, and bring it in contact with a minute granule or crystal of strychnine. Similar colours will appear whenever the alkaloid is brought in contact with the mixture, e. Proceed in the same way with the peroxide of lead. The same colours wjU be