The ripe berries of cultivated Atropa belladonna nigra contain atropine and hyoscyamine; those of the wild plant contain atropine only; the ripe fruit of Atropa belladonna lutea contains only atropine and another base, perhaps identical with atropamine; the unripe fruit of wild Atropa belladonna nigra contains hyoscyamine, with only a small quantity of atropine.
The leaves of the yellow and black-fruited wild Atropa belladonna contain hyoscyamine and atropine, the latter being in small quantity only.
Fresh and old seeds of Datura Stramonium contain chiefly hyoscyamine; small quantities of atropine and scopolamine are also present.
§ 442. The Datura Stramonium or Thorn-apple is also indigenous in the British Islands, but, like belladonna, it cannot be considered a common plant. Datura belongs to the Solanaceæ; it grows from 1 to 2 feet in height, and is found in waste places. The leaves are smooth, the flowers white; the fruit is densely spinous (hence the name thorn-apple), and is divided into four dissepiments below, two at the top, and containing many seeds.
The Datura, or the Dhatura-plants, of India have in that country a great toxicological significance, the white-flowered datura, or Datura alba, growing plentifully in waste places, especially about Madras. The purple-coloured variety, or Datura fastuosa, is also common in certain parts. There is a third variety, the Datura atrox, found about the coast of Malabar. The seeds of the white datura have been mistaken in India for those of capsicum. The following are some of the most marked differences:—
| Seeds of the Common or White Datura. | Seeds of Capsicum. |
|---|---|
| (1.) Outline angular. | Outline rounded. |
| (2.) Attached to the placenta by a large, white, fleshy mass separating easily, leaving a deep furrow along half the length of the seed’s concave border. | Attached to the placenta by a cord from a prominence on the concave border of the seed. |
| (3.) Surface scabrous, almost reticulate, except on the two compressed sides, where it has become almost glaucous from pressure of the neighbouring seeds. | Uniformly scabrous, the sides being equally rough with the borders. |
| (4.) Convex border thick and bulged with a longitudinal depression between the bulgings, caused by the compression of the two sides. | Convex border thickened, but uniformly rounded. |
| (5.) A suitable section shows the embryo curved and twisted in the fleshy albumen. | The embryo, exposed by a suitable section, is seen to resemble in outline very closely the figure 6. |
| (6.) The taste of the datura seeds is very feebly bitter. The watery decoction causes dilatation of the pupil. | The taste of capsicum is pungent; a decoction irritates the eye much, but does not cause dilatation of the pupil. |
The identity of the active principle in both the datura and belladonna tribes is now completely established.[486]
[486] See a research by Ernst Schmidt, “Ueber die Alkaloide der Belladonna-Wurzel u. des Stechapfel-Samens,” Lieb. Annl., Bd. 208, 1881.