Cytisine forms numerous crystalline salts, among which may be mentioned two platinochlorides, C11H14N2OH2PtCl6 + 21⁄2H2O and (C11H14N2O)2H2PtCl6, crystallising in golden yellow needles, which are tolerably soluble in water; and the aurochloride, C11H14N2OHAuCl4, crystallising in short, red-brown, hook-shaped needles; m.p. 212° to 213°, without evolution of gas.
§ 467. Reactions of Cytisine.—Concentrated sulphuric acid dissolves cytisine without colour; if to the solution is added a drop of nitric acid, it becomes orange-yellow, and on addition of a crystal of potassic bichromate, first yellow, then dirty brown, and lastly green. Concentrated nitric acid dissolves the base in the cold without colour, but, on warming, it becomes orange-yellow. Picric, tannic, and phosphomolybdic acids, potassic, mercuric, and potass. cadmium iodides, and iodine with potassic iodide, all give precipitates. Neither potassic bichromate nor mercuric chloride precipitates cytisine, even though the solution be concentrated. The best single test appears to be the reaction discovered by Magelhaes; this consists in adding thymol to a solution of cytisine in concentrated sulphuric acid, when a yellow colour, finally passing into an intense red, is produced.
§ 468. Effects on Animals.—W. Marmé found subcutaneous doses of from 30 to 40 mgrms. fatal to cats; death was from paralysis of the respiration, and could be avoided by artificial respiration. Cattle are sometimes accidentally poisoned by laburnum. An instance of this is recorded in the Veterinarian (vol. lv. p. 92). In Lanark a storm had blown a large laburnum tree down to the ground; it fell into a field in which some young heifers were grazing, and they began to feed on the leaves and pods. Two or three died, and three more were ill for some time, but ultimately recovered.
The laburnum, however, does not always have this effect, for there is a case related in the Gardeners’ Chronicle, in which five cows browsed for some time on the branches and pods of an old laburnum tree that had been thrown aside. Rabbits and hares are said to feed eagerly, and without injury, on the pods and branches.
§ 469. Effects on Man.—The sweet taste of many portions of the laburnum tree, as well as its attractive appearance, has been the cause of many accidents. F. A. Falck has been able to collect from medical literature no less than 155 cases—120 of which were those of the accidental poisoning of children: only 4 (or 2·6 per cent.), however, died, so that the poison is not of a very deadly character.
One of the earliest recorded cases is by Christison.[519] A servant-girl of Inverness, in order to excite vomiting in her fellow-servant (the cook), boiled some laburnum bark in soup; very soon after partaking of this soup, the cook experienced violent vomiting, which lasted for thirty-six hours; she had intense pain in the stomach, much diarrhœa, and great muscular weakness; she appears to have suffered from gastro-intestinal catarrh for some time, but ultimately recovered.
[519] Ed. Med. Journ., 1843.
Vallance[520] has described the symptoms observed in the poisoning of fifty-eight boys, who ate the root of an old laburnum tree, being allured by its sweet taste. All were taken ill with similar symptoms, differing only in severity; two who had eaten half an ounce (nearly 8 grms.) suffered with especial severity. The symptoms were first vomiting, then narcosis, with convulsive movements of the legs and strange movements of the arms: the pupils were dilated. This dilatation of the pupil Sedgwick also saw in the poisoning of two children who ate the root. On the other hand, when the flower, seeds, or other portions of the laburnum have been eaten, the symptoms are mainly referable to the gastro-intestinal tract, consisting of acute pain in the stomach, vomiting, and diarrhœa. On these grounds it is therefore more than probable that there is another active principle in the root, differing from that which is in those portions of the tree exposed to the influence of sunlight.[521]