[365] Phil. Trans., 1851.
Sparteine is separated from the plant by extraction with sulphuric acid holding water, and then alkalising the acid solution and distilling: it has the formula (C15H26N2), and belongs to the class of tertiary diamines. It is a clear, thick, oily substance, scarcely soluble in water, to which it imparts a strong, alkaline reaction; it is soluble in alcohol, in ether, and chloroform; insoluble in benzene and in petroleum; it boils at 288°. Sparteine neutralises acids fully, but the oxalate is the only one which can be readily obtained in crystals. It forms crystalline salts with platinic chloride, with gold chloride, with mercuric chloride, and with zinc chloride. The picrate is an especially beautiful salt, crystallising in long needles, which, when dried and heated, explode. On sealing sparteine up in a tube with ethyl iodide and alcohol, and heating to 100° for an hour, ethyl sparteine iodide separates in long, needle-like crystals, which are somewhat insoluble in cold alcohol.
Effect on Animals.—A single drop kills a rabbit; the symptoms are similar to those produced by nicotine, but the pupils are dilated.[366]
[366] To the nicotine group, gelsemine (C24H28N2O4) and oxalathylin (C6H10N2) also belong, in a physiological sense, but gelsemine, like sparteine, dilates the pupil.
5. ANILINE.
§ 340. Properties.—Aniline or amido-benzol (C6H5NH2) is made by the reduction of nitro-benzol. It is an oily fluid, colourless when quite pure, but gradually assuming a yellow tinge on exposure to the air. It has a peculiar and distinctive smell. It boils at 182·5°, and can be congealed by a cold of 8°. It is slightly soluble in water, 100 parts of water at 16° retaining about 3 of aniline, and easily soluble in alcohol, ether, and chloroform. It does not blue red-litmus paper, but nevertheless acts as a weak alkali, for it precipitates iron from its salts. It forms a large number of crystalline salts. The hydrochloride crystallises in white plates, and has a melting-point of 192°. The platinum compound has the formula of (C6H5NH2HCl)2PtCl4, and crystallises in yellow needles.
§ 341. Symptoms and Effects.—Aniline, like picric acid, coagulates albumin. Aniline is a blood poison; it produces, even during life, in some obscure way, methæmoglobin, and it disintegrates the red blood corpuscles; both these effects lessen the power of the blood corpuscles to convey oxygen to the tissues, hence the cyanosis observed so frequently in aniline poisoning is explained. Engelhardt[367] has found that aniline black is produced; in every drop of blood there are fine black granules, the total effect of which produce a pale blue or grey-blue colour of the skin. Aniline has also an action on the central nervous system, at first stimulating, and then paralysing. Schmiedeberg finds that para-amido-phenol-ether-sulphuric acid is produced, and appears in the urine as an alkali salt; a small quantity of fuchsine is also produced, and has been found in the urine. Some aniline may be excreted unchanged.