3. HYOSCINE.
§ 460. Hyoscine, C17H23NO3.—According to E. Schmidt[512] the formula is C17H21NO4 + H2O, and the alkaloid is identical with scopolamine. Scopolamine has a m.p. of 59°, gives an aurochloride, crystallising in needles, the m.p. of which is 212° to 214°; when boiled with baryta water, it splits up into atropic acid and scopoline, a base (C8H13NO), m.p. 110°, boiling-point, 241° to 243°; scopoline forms an aurochloride, m.p. 223°-225°; and a platinochloride, m.p. 228°-230°; but Ladenburg,[513] in answer to Schmidt, asserts that hyoscine exists, and is not identical with scopolamine. A sample of commercial hyoscine hydrobromide Nagelvoort found to melt, water-free, at 198°; other commercial samples of hydrobromide melted at 179° and 186°; the latter sample giving an aurochloride which melted at 192°. Pure hyoscine gold chloride is stated to melt at 198°. Its reactions are much the same as those of atropine, but it does not blacken calomel. It is very poisonous.
[512] Arch. Pharm., ccxxx. 207-231.
[513] Ber., xxv. 2388-2394.
According to experiments on animals, the heart is first slowed, then quickened; the first effect being due to a stimulation of the inhibitory nervous apparatus, the second to a paralysing action on the same. The temperature is not altered. The pupils are dilated, the saliva diminished. The irritability of the brain is lessened.[514]
[514] Parloff, St Petersburg Med. Chem. Acad., Dissert. No. 9, 1889-90.