§ 326. Post-mortem Appearances.—There is nothing characteristic in the appearances after death.
Fatal Dose.—The fatal dose of coniine is not accurately known; it is about 150 mgrms. (2·3 grains). In the case of Louise Berger, 10 to 15 drops appear to have caused death in a few minutes. The auto-experiments of Dworzak, Heinrich, and Dillaberger would indicate that one drop may cause unpleasant symptoms. Albers, in the treatment of a woman suffering from cancer of the breast, witnessed convulsions and loss of consciousness from a third dose of 4 mgrms. (·06 grain); and Eulenberg, its full narcotic effects on a child after subcutaneous injection of 1 mgrm. (·015 grain).
§ 327. Separation of Coniine from Organic Matters or Tissues.—The substances are digested with water, acidulated with H2SO4, at a temperature not exceeding 40°, and then filtered. If the filtrate should be excessive, it must be concentrated; alcohol is then added, the liquid refiltered, and from the filtrate the alcohol separated by distillation.
On cooling, the acid fluid is agitated with benzene, and the latter separated in the usual way. The fluid is now alkalised with ammonia, and shaken up once or twice with its own volume of petroleum ether; the latter is separated and washed with distilled water, and the alkaloid is obtained almost pure. If the petroleum ether leaves no residue, it is certain that the alkaloid was not present in the contents of the stomach or intestine.
The affinity of coniine with ether or chloroform is such, that its solution in either of these fluids, passed through a dry filter, scarcely retains a drop of water. In this way it may be conveniently purified, the impurities dissolved by water remaining behind.
In searching for coniine, the stomach, intestines, blood, urine, liver, and lungs are the parts which should be examined. According to Dragendorff, it has been discovered in the body of a cat six weeks after death.
Great care must be exercised in identifying any volatile alkaloid as coniine, for the sources of error seem to be numerous. In one case[348] a volatile coniine-like ptomaine, was separated from a corpse, and thought to be coniine; but Otto found that in its behaviour to platinic chloride, it differed from coniine; it was very poisonous—·07 was fatal to a frog, ·44 to a pigeon, in a few minutes. In the seeds of Lupinus luteus there is a series of coniine-like substances,[349] but they do not give the characteristic crystals with hydrochloric acid.
[348] Otto, Anleitung z. Ausmittlung d. Gifte, 1875.
[349] Sievert, Zeitschrift für Naturwissenschaften.