GRANATEÆ.
CORTEX GRANATI FRUCTUS.
Cortex Granati; Pomegranate Peel; F. Ecorce de Grenades; G. Granatschalen.
Botanical Origin—Punica Granatum L., a shrub or low tree, with small deciduous foliage and handsome scarlet flowers. It is indigenous to North-western India, and the counties south and south-west of the Caspian to the Persian Gulf and Palestine, and grows wild in the hills of Western Sindh in elevations of 4000 feet, in Balutchistan to 6000 feet, also in the east flank of Soliman range. The trunk is short, rarely over 20 feet high. The tree has long been cultivated, and is now found throughout the warm parts of Europe, and in the subtropical regions of both hemispheres.
History—The pomegranate has been highly prized by mankind from the remotest antiquity, as is shown by the references to it in the Scriptures,[1109] and by the numerous representations of the fruit in the sculptures of Persepolis and Assyria,[1110] and on the ancient monuments of Egypt.[1111] It was probably introduced into the south of Italy by Greek colonists, and is named as a common fruit-tree by Porcius Cato[1112] in the 3rd century b.c. The peel of the fruit was recognized as medicinal by the ancients, and among the Romans was in common use for tanning leather,[1113] as it still is in Tunis.
Description—The fruit of the pomegranate tree is a spherical, somewhat flattened and obscurely six-sided berry, the size of a common orange and often much larger, crowned by the thick, tubular, 5-to 9-toothed calyx. It has a smooth, hard, coriaceous skin, which when the fruit is ripe, is of a brownish yellow tint, often finely shaded with red. Membranous dissepiments, about 6 in number meeting in the axis of the fruit, divide the upper and larger portion into equal cells. Below these a confused conical diaphragm separates the lower and smaller half, which in its turn is divided into 4 or 5 irregular cells. Each cell is filled with a large number of grains, crowded on thick spongy placentæ, which in the upper cells are parietal but in the lower appear to be central. The grains, which are about ½ an inch in length, are oblong or obconical and many-sided, and consist of a thin transparent vesicle containing an acid, saccharine, red, juicy pulp, surrounding an elongated angular seed.
The only part of the fruit used medicinally is the peel, Cortex Granati of the druggists, which in the fresh state is leathery. When dry as imported, it is in irregular, more or less concave fragments, some of which have the toothed, tubular calyx still enclosing the stamens and style. It is ⅒ to ¹/₂₀ of an inch thick, easily breaking with a short corky fracture; externally it is rather rough, of a yellowish-brown or reddish colour. Internally it is more or less brown or yellow, and honey-combed with depressions left by the seeds. It has hardly any odour, but has a strongly astringent taste.
Microscopic Structure—The middle layer of the peel consists of large thin-walled and elongated, sometimes even branched cells, among which occur thick-walled cells and fibro-vascular bundles. Both the outer and the inner surface are made up of smaller, nearly cubic and densely packed cells. Small starch granules occur sparingly throughout the tissue, as well as crystals of oxalate of calcium.
Chemical Composition—The chief constituent is tannin, which in an aqueous infusion of the dried peel produces with perchloride of iron an abundant dark blue precipitate. The peel also contains sugar and a little gum. Dried at 100° C. and incinerated, it yielded us 5·9 per cent. of ash.
Uses—Pomegranate peel is an excellent astringent, now almost obsolete in British medicine. Waring[1114] chronic dysentery of the natives of India, as well as in diarrhœa.