Source, Etc

The henbane plant, Hyoscyamus niger; Linne (N.O. Sola-nacece), has been already alluded to (p. 49). The fruit of the plant is a small two-celled capsule, which dehisces transversely, the upper part separating from the lower like the lid of a box (pyxis). Within the fruit is a large number of minute seeds; these, separated when ripe, form the commercial drug.

Description

Henbane seeds are dark grey, about 1.5 mm. long, flattened and obscurely reniform in shape, being slightly pointed at one extremity (the hilum). Under a strong lens the surface, which appears dull to the naked eye, is seen to be marked with very characteristic reticulations. Cut longitudinally, parallel to the flat surface, the seed exhibits a coiled embryo embedded in an oily endosperm.

The seeds have no odour and only a slightly bitter taste.

The student should carefully observe

(a) The small size and flattened sub-reniform shape,

(b) The reticulate surface; and should compare them with

(i) Poppy seeds, which are distinctly reniform, and have larger and shallower reticulations on the surface, (ii) Thornapple seeds, which are much larger and darker,

Description 149Description 150Description 151Fig. 96.   Henbane seed. A, entire fruit, showing dehiscence. B, the same cut vertically. C, seed, cut longitudinally. (Luerssen.) D, seed, showing reticulate surface. Magnified.

Fig. 96. - Henbane seed. A, entire fruit, showing dehiscence. B, the same cut-vertically. C, seed, cut longitudinally. (Luerssen.) D, seed, showing reticulate surface. Magnified.

Constituents

The principal constituent of henbane seed is the alkaloid hyoscyamine with which is associated a small proportion of scopolamine (hyoscine).

The total amount of alkaloid is 0.058 per cent. (Ransom, 1891). In addition, the seed contains about 20 per cent, of fixed oil.

Uses

Henbane seeds are comparatively seldom used in medicine. Thrown upon hot coals they form a domestic remedy for toothache the vapour that arises being allowed to enter the mouth. They have been used as a source of the alkaloid scopolamine.