In a few exceptional cases there has been no appearance of inflammation in the stomach or bowels.
Putrefaction of the body is said to be remarkably retarded after death from arsenic.
Treatment.—The first object must be to expel the poison from the stomach, for which purpose the stomach-pump may be advantageously employed, or emetics of sulphate of zinc, mustard, or ipecacuan administered, unless vomiting is already present. The sickness must be promoted by the free use of albuminous or mucilaginous diluents. Raw eggs beaten up in milk are particularly useful, as is likewise a mixture of albumen, milk, and limewater. Taylor advises equal parts of oil and limewater, for the oil invests the poison, and the lime renders it less soluble. A large dose of castor oil (℥j to ℥ij) may be given, to carry off any of the poison which may have passed into the intestines, as soon as sickness has subsided. Animal charcoal, calcined magnesia, &c., when taken in large quantities, may be of service by enveloping the arsenic, and preventing its contact with the mucous membrane of the stomach; but oil or milk will act more efficiently in this manner. The hydrated peroxide of iron[B] should be administered moist, and in large doses, after the stomach-pump has been used; or indeed, mixed with water, it may be first introduced and then expelled, thus washing out the stomach by means of the stomach-pump. This is the most efficient antidote known.
The subsequent treatment must be conducted on general principles, according to the severity of the symptoms; but the great depression of the nervous and vascular systems must not be overlooked in combating any inflammatory action. Henbane or opium, in many instances combined with stimulants, ice internally, and hot fomentations externally, will frequently be found of great service.
Tests.—In its solid state arsenious acid may be known by the following properties. Heated on platinum foil or on the point of a penknife, it produces a white smoke and is entirely volatilized. If some of the powder be heated in a small test tube, it will be sublimed, and small octahedral crystals, visible to the naked eye or by a lens, obtained. If arsenious acid be mixed with freshly-burnt powdered charcoal, and heated in a small test tube, a ring of shining metallic arsenic of a grey color will be found on the cool portion of the tube, and an odor of garlic is perceptible. If this deposit be driven about from place to place it will gradually become oxidized, and octahedral crystals of arsenious acid formed. Further, if the tube be divided and the part containing the arsenious acid be washed out with distilled water, the liquid tests may be applied to the solution. This is called the Reduction test. It is very delicate, detecting according to Christison, the 300th part of a grain.
In solution, this substance may be detected by what are called the liquid tests. A solution of arsenic in water is colorless, almost tasteless, and has a very slightly acid reaction. If a few drops be evaporated on a glass slide and examined by the microscope, numerous minute and mostly imperfect octahedral crystals, or an amorphous deposit, will be seen, presenting triangular surfaces by reflected light.
1. The ammonio-nitrate of silver (prepared by adding a few drops of liquor ammoniæ to a solution of nitrate of silver, till the brown oxide of silver at first precipitated is nearly redissolved) throws down with arsenious acid a rich yellow deposit of arsenite of silver.
2. The ammonio-sulphate of copper (formed by adding liquor ammoniæ to a solution of sulphate of copper till the bluish-white oxide of copper is almost redissolved) produces a pale green precipitate, arsenite of copper, or Scheele’s green. Care must be taken not to add too much of the test in the first instance, otherwise its blue may overpower the green of the precipitate.
3. Sulphuretted hydrogen water precipitates a yellow deposit of sulphide of arsenic. It is better, however, to use pure and well-washed sulphuretted hydrogen generated in the usual manner. Care must be taken that the liquid is not alkaline, or no precipitate will be produced, even though arsenic be present. For this reason yellow sulphide of ammonium will not precipitate arsenic until acidulated with pure hydrochloric or some such acid. The precipitate should be collected, carefully washed, and dried. It should then be mixed with black flux or dry ferrocyanide of potassium and reduced, as already described.
These tests are so delicate, especially the first, that they will detect the 8000th part of a grain of arsenic in solution; they should be employed successively. There are several other processes which require to be noticed, namely, Marsh’s process, the process known as Reinsch’s process, Fresenius’s process, and the Destillation process.