"The unexpanded flowers of Eugenia aromatica, (Linné), O. Kuntze"—(U. S. P.). (Eugenia caryophyllata, Thunberg; Caryophyllus aromaticus, Linné; Myrtus caryophyllatus, Sprengel).
COMMON NAME AND SYNONYM: Cloves; Caryophylli aromatici.
ILLUSTRATION: Bentley and Trimen, Med. Plants, 112.
Botanical Source.—Eugenia aromatica is a beautiful tree, rising to the height of 15 or 20 feet. It is of a conical or pyramidal form, evergreen, and the whole plant is glabrous. Its branches are numerous, slender, opposite, and more or less virgate. The wood of the stem is hard; the bark grayish and smooth. The leaves are opposite and decussate, persistent, somewhat coriaceous and shining, minutely punctated, about 4 inches long and half as broad, ovate-lanceolate, more or less acute, quite entire, pale beneath, and tapering gradually at the base, into a slender foot-stalk, which is nearly 2 inches long. The flowers are very odoriferous, and are in short, terminal many-flowered panicles, trichotomously divided and jointed at every division. Peduncles terete and green. The calyx is composed of 4 ovate, concave segments, erecto-patent, placed upon the top of the ovary, and together with it, is first green, and then red and coriaceous. The petals are 4, larger than the calyx, imbricated into a globe in bud, at length spreading, roundish, concave, yellowish-red, and very soon caducous. In the center of the calyx, and occupying the top of the ovary, is a quadrangular, elevated line or gland, surrounding, but not embracing, the base of the shortish, obtusely-subulate style. Around this gland, immediately within the petals, the stamens are inserted. These are longer than the petals, yellow, and with small, yellow, ovate-cordate, 2-celled anthers. The ovary is oblong, almost cylindrical, and 2-celled, with many small ovules in each cell. The berry is purplish, elliptical, and 2-seeded. The seed is covered with a thin integument of a soft texture (L.).
History.—A tall and beautiful tree, growing in tropical climates, extinct in its first habitat (Clove Islands), but introduced and extensively cultivated on the East Africa coast, and in the East and West Indies, and Brazil. The cultivated tree, from which the cloves are gathered, is not so tall as in the wild state, but its aromatic properties are much more pronounced. The flowers are collected twice yearly, in June and December, before they are fully developed, and just as they become bright-red, being either hand-picked or knocked from the tree with bamboo poles, falling upon a cloth outstretched to receive them. They consist of a tubular calyx, bearing a roundish bud of unexpanded petals; they are quickly dried in the sun, becoming thereby brown. The finest kinds are plump, heavy, and dark, and give out oil when squeezed with the nail. These are usually from East Africa and the Moluccas. A lighter-colored, shrunken variety comes from South America and the West Indies. Occasionally cloves from which the oil has been partially extracted, appear in market mixed with the better qualities. As a rule, they are deprived of their heads, and are in a moist state.
Description.—"About 15 Mm. (½ inch) long, dark-brown, consisting of a subcylindrical, solid and glandular calyx-tube, terminated by 4 teeth, and surmounted by a globular head, formed by 4 petals, which cover numerous curved stamens, and 1 style. Cloves emit oil when scratched, and have a strong, aromatic odor, and a pungent, spicy taste"—(U S. P.). They yield their virtues to alcohol, spirit, and ether; water merely acquires their aroma.
Chemical Composition.—Cloves contain volatile oil, fixed oil, a peculiar tannin, gum, resin, fiber, water, and two crystalline principles called caryophyllin (C20H32O) and eugenin (C10H12O2) (Trommsdorff). Caryophyllin is a camphor-like body which occurs in silky, needle-like prisms, without taste or odor, and of neutral reaction. It was isolated by Lodibert in 1825. Eugenin occurs in pearly white laminae, without taste. It was obtained in 1833, from the aqueous distillate of cloves, by Dumas, and named by Bonastre. Caryophyllin may be prepared by treating cloves previously deprived of the greater part of their volatile oil by means of a small quantity of alcohol, with hot ether. When treated with nitric acid it yields crystalline caryophyllinic acid (C20H32O6) (E. Mylius, 1873). The active properties reside in the volatile oil, which is colorless or of a pale-yellow color, darkens by age, and is heavier than water. The yield from cloves is from 16 to 20 per cent. It is extremely pungent and acrid, and its principal constituent is eugenol (C10H12O2), a fluid body (see Oleum Caryophylli).
Action, Medical Uses, and Dosage.—Aromatic, stimulant, and irritant. Used to allay vomiting and sickness at stomach, to stimulate the digestive functions, and to improve the flavor or operation of other remedies, and prevent a tendency to their producing sickness or griping. Dose, from 6 to 10 grains.
Substituted Drugs and Related Species.—CLOVE STALKS. The dividing flower-stalks of cloves are frequently powdered to adulterate ground cloves, and occasionally are met in commerce intact. They have a pale-brownish hue, are about a line in thickness, and possess the characteristic clove taste and odor, though in feeble degree as compared with genuine cloves. They yield about ⅕ as much essential oil as the latter, and are used to some extent in the distillation of clove oil. Their presence in powdered cloves maybe shown microscopically by stone-cells (examined in glycerin after being treated with caustic potash), which are not found in clove-buds.
MOTHER CLOVES, Anthophylli.—Nearly ripe, dried clove-fruits. Oblong-oval, calyx-crowned, nearly an inch in length, resembling cloves to some extent, though yielding much less cloveoil. Microscopically detected in ground cloves by starch-cells of large size.
ROYAL CLOVES, Caryophyllum regium.—A monstrosity clove, small, having imperfect floral organs, sepals abnormal, and calyx-tube with bracts at base. Rare (Pharmacographia).
ALLSPICE (see Pimenta).—Occasionally used as an adulterant of ground cloves. Microscopically shown by starch-cells, together with stone-cells.
Dianthus Caryophyllus.—The clove pink, selecting the deep-red and most fragrant flowers, is used in Europe to flavor and color a syrup.