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The witch-hazel, Hamamelis virginiana, Linne (N.O. Hamamelideœ), is a common shrub in the United States and Canada. It attains a height of about 3 metres, and resembles the common hazel both in its leaves and in its fruit, which is edible. Both the fresh and dried leaves are official, the former being employed for the preparation of Liquor Hamamelidis. The bark is also used in medicine.

Description

Commercial witch-hazel leaves are usually in a somewhat indifferent state of preservation, being frequently discoloured, broken, and pressed together into more or less compact masses. Well-preserved full-grown leaves are of a dark green or brownish green colour, and attain 15 cm. in length by 10 cm. in breadth. They are broadly oval or rounded-obovate, the lamina tapering somewhat towards the base, where it is decidedly oblique, usually cordate, and provided with a short petiole; the apex is acuminate, but is often imperfect and then frequently obtuse. The margin is coarsely crenate or even sinuate. On the under surface the midrib is prominent, and the lateral veins, which are also very distinct, branch from it at an acute angle, and run straight to and terminate in the crenations of the margin. In the angles thus formed and on the veins, hairs, which will be seen under the lens to have a characteristic branching form, are usually to be found; they are more frequent on young leaves, very young leaves being brown in colour and densely hairy. The leaves have only a slight odour, but a decidedly astringent and somewhat bitter taste. The student should observe

(a) The sinuate margin,

(b) The lateral veins running straight to the margin,

(c) The branching hairs.

Constituents

Witch-hazel leaves have not yet been subjected to careful analysis. They contain gallic acid, tannin, a bitter principle, and a trace of volatile oil. By distilling the fresh or dry leaves with water or dilute alcohol, a distillate is obtained possessing a distinct aroma, different from that of the leaves themselves, due probably to some product of decomposition. The official Liquor Hamamelidis, which is made by macerating the fresh leaves with dilute alcohol and distilling, contains, in addition to the aromatic body alluded to, a trace of protocatechuic acid.

Hamamelin is a mixture of substances obtained by extracting the leaves, or sometimes the bark,with strong alcohol and evaporating the tincture thus obtained.

The autumnal leaves are said to contain most tannin and to be distinguishable by the hairs, which have thicker walls, are yellow in colour, and devoid of contents (Cooley, 1900).

Uses

Witch-hazel leaves are astringent and haemostatic; they are useful as a local application in haemorrhage from the nose, etc.

Fig. 26.   Witch hazel leaf.

Fig. 26. - Witch-hazel leaf.