The heart is flabby, red in the substance, and the pericardium contains serum. In the thorax the pleura is red, and its sac often containing serum; the lungs are congested, and the lining membrane of the air tubes is inflamed. In the cranium the brain is found congested: but when death is less the consequence of inflammation than of a peculiar and immediate influence of the poison upon the nervous system, no morbid change is discoverable on dissection. Particles of the acid are occasionally found adhering to the abraded parts of the villous coat of the stomach.

1 In a case detailed by Dr. Yelloly, no pain of the stomach, convulsions, nor delirium occurred, although it terminated fatally. Edin. Med, and Surg. Journ, v. 389.

Various methods of counteracting the poison of the arsenious acid have been recommended. Whatever antidote is adopted, the stomach should, in all cases, be immediately evacuated; and the best mode of doing this is by means of the stomach pump, administering large draughts of tepid mucilaginous fluids. In order to render the arsenic inert, solutions of the alkaline sulphurets and vinegar have been advised: but the experiments of Renault have demonstrated how little reliance is to be placed on these articles. Hahneman orders one pound of soap to be dissolved in four pounds of water, and a cupful taken, tepid, every three or four minutes; and as this is the antidote most readily procured, if lime-water or chalk and water cannot be at hand, it should always be the first employed. Lime-water proves useful by coating the particles of the white arsenic with an arsenite of lime, which is nearly insoluble, and consequently almost inert.2 Dr. Yelloly, reasoning on the probability that the inflammation induced is often the cause of death, even after the stomach is freed from the whole of the poison, suggests the propriety of early bloodletting in these cases.3 Opium, camphor, and ether may be employed to quiet the nervous irritability, and ammonia to stimulate the heart.

1 On this subject our readers will find much practical information in the London Medical Repository, vol. v. p. 97., and still more in Dr. Christison's excellent work on Poisons, p. 177.

2 See our experiments on this subject, in the London Med. Repos., vol. viii. 157.

3 Edinburgh Med. and Surg. Journal, v. 392.

As medical men are often called upon in courts of law to establish the fact of white arsenic having been used as a poison, it is necessary to know the best tests by which it may be recognised. If on searching in the stomach, or among its vomited contents, any considerable quantity of the suspected poison be discovered, a little of it must be mixed with three times its weight of black flux, composed of one part of finely-powdered charcoal, and two parts of dry carbonate of potassa; or, to a grain of the poison add half a grain of charcoal, and a grain of dried carbonate of potassa. These must be put into a thin glass tube, about four inches in length and l-4th inch in diameter, hermetically closed at one end. (Jig. a.) The open extremity must then be slightly plugged with a piece of paper, taking care to preserve clean the upper portion of the tube, by introducing the powder by means of a small funnel (fig. b.) or a cylinder of clean white paper. The tube, being thus charged, should be kept for a quarter of an hour in the flame of a spirit lamp, heating it first above the bulb, and then holding the bulb steadily in the flame of the lamp: when, if the powder introduced into the tube contain arsenious acid, metallic arsenic will sublime and be found lining the inside of the tube with a brilliant metallic crust.

The upper part of the material should always be heated first with a small flame; then, the wick of the lamp being drawn up, the heat should be applied to the bottom of the tube. That the sublimated matter is arsenic may be further proved by volatilizing a small portion of the reduced metal on a red-hot iron, and observing whether it present the garlic odour peculiar to the vapour of metallic arsenic: or if the crust be small, by cutting off the bulb of the tube, and heating the part containing the crust, so as to oxidize it; and then testing the acid by the under-mentioned tests.

When the poison is found in a larger quantity, it should be further tested by dissolving a small portion of it in two drachms of boiling rain or distilled water, with three grains of subcar-bonate of potassa, or, what is to be preferred, the subcar-bonate of ammonia, then adding to this a warm solution of five grains of sulphate of copper, which will produce a lively grass-green precipitate if arsenic be present; and if the precipitate be heated in a test-tube with a little wax, it will sublime in the form of metallic arsenic. A solution of some of the suspected poison may be made, without the addition of an alkali, and tested with the ammoniacal sulphate of copper1, which immediately throws down a beautiful apple-green precipitate; or with the ammoniacal nitrate of silver2, which throws down a sulphur yellow arsenite of silver. When no powder is discovered in the stomach, its contents and the vomited matter may be boiled with distilled water, with the addition of some pure potassa, and filtered; and then a warm solution of the sulphate of copper, as above described, added to it. Mr. Phillips, however, has shown that if the sulphate contain any peroxide of iron, it will afford a green precipitate, although no arsenic be present.

To prevent this fallacy, he directs the potassa to be added to the sulphate of copper first, and to a part of this the suspected solution, when the blue precipitate will become green, if arsenious acid be present. The test with nitrate of silver was first proposed by Mr. Hume3: one part of the suspected poison, and three parts of subcar-bonate of potassa are to be dissolved in a sufficient quantity of rain or distilled water at 212°; and the surface of this solution slightly touched with a stick of nitrate of silver. If arsenious acid be present, a sulphur-yellow coloured precipitate will be seen falling rapidly from the point where the nitrate is applied. In our experiments we have found that the sixtieth part of a grain of the acid is clearly discovered in two ounces of water by this test. This precipitate, which is arsenite of silver, should afford, when heated with wax, indications of metallic arsenic, as in the former case. All these experiments should be performed in the day-time, and the precipitated fluid examined by reflected, not transmitted, light.4 Objections have been raised against the nitrate and ammoniated nitrate of silver, because the presence of the alkaline phosphates in the suspected fluid would produce precipitates of a similar colour with nitrate of silver; and if muriate of soda, or of any other alkali, were present, the test could not be employed, on account of the copious precipitates of chloride of silver which these produce with the nitrate.