VI.—The Mydriatic Group of Alkaloids—Atropine—Hyoscyamine—Solanine—Cytisine.
1. ATROPINE.
§ 441. Atropine (Daturine), C17H23NO3.—This important alkaloid has been found in all parts of the Atropa belladonna, or deadly nightshade, and in all the species of Datura.
The Atropa belladonna is indigenous, and may be found in some parts of England, although it cannot be said to be very common. It belongs to the Solanaceæ, and is a herbaceous plant with broadly ovate entire leaves, and lurid-purple axillary flowers on short stalks; the berries are violet-black, and the whole of the plant is highly poisonous. The juice of the leaves stains paper a purple colour. The seeds are very small, kidney-shaped, weighing about 90 to the grain; they are covered closely with small, round projections, and are easily identified by an expert, who may be supposed to have at hand (as is most essential) samples of different poisonous seeds for comparison. The nightshade owes its poisonous properties to atropine.
The yield of the different parts of belladonna, according to Gunther,[483] is as follows:—
[483] Pharm. Zeitschr. f. Russl., Feb., 1869; Dragendorff, Die chemische Werthbestimmung einiger starkwirkenden Droguen, St. Petersburg, 1874.