The Portuguese had the principal share in the clove trade for nearly a century. In 1605 they were expelled by the Dutch, who took exclusive possession of the Moluccas and adopted extraordinary measures for keeping the traffic in their own hands. Yet notwithstanding this, large supplies of cloves reached England direct. In 1609 a ship of the East India Company called the Consent arrived with 112,000 lb., the duty on which amounted to £1400 and the impost to as much more. The spice ungarbled was sold at 5s. 6d. and 5s. 9d. per lb.—of course, in bond.[1090]
To effect their purpose, the Dutch endeavoured to extirpate the clove-tree from its native islands, and even instituted periodical expeditions for the purpose of destroying any young trees that might have accidentally sprung up. This policy, the object of which was to confine the growth of the spice to a group of small islands of which Amboyna is the largest, has but very recently been abandoned: though the cultivation of the spice was free in all other localities, the clove parks of the Amboyna islands remained the property of the Dutch Government. The original Moluccas or Clove Islands now produce no cloves at all.
The enterprise of Poivre, the French governor of Mauritius and Bourbon, so far eluded the vigilance of the Dutch, that both clove and nutmeg-trees were introduced into those islands in the year 1770.[1091] The clove-tree was carried thence to Cayenne in 1793, and to Zanzibar about the end of the century.
Crawfurd,[1092] in an excellent article of which we have made free use, aptly remarks that it is difficult to understand how the clove first came to the notice of foreign nations, considering the well ascertained fact that it has never been used as a condiment or in any other way by the inhabitants of the islands of which it is a native. We may observe however that there were some singular superstitions among the islanders with regard to the so-called Royal Clove ([p. 287]), a tree of which on the island of Makiyan was long supposed to be unique.
Collection—The flower-buds of the clove-tree when young are nearly white, but afterwards become green and lastly bright red, when they must at once be gathered. This in Zanzibar is done by hand; each clove is picked singly, a moveable stage the height of the tree being used to enable the labourers to reach the upper branches. The buds are then simply dried in the sun, by which they acquire the familiar dark brown tint of the commercial article. The gathering takes place twice a year; in the Moluccas where the harvest occurs in June and December, the cloves are partly gathered by hand, and partly beaten off the tree by bamboos on to cloths spread beneath. The annual yield of a good tree is about 4½ pounds, but sometimes reaches double that quantity.
Description—Cloves are about ⁶/₁₀ of an inch in length, and consist of a long cylindrical calyx dividing above into 4 pointed spreading sepals which surround 4 petals, closely imbricated as a globular bud about ²/₁₀ of an inch in diameter.
The petals which are of lighter colour than the rest of the drug and somewhat translucent from numerous oil-cells, spring from the base of a 4-sided epigynous disc, the angles of which are directed towards the lobes of the calyx. The stamens which are very numerous, are inserted at the base of the petals and are arched over the style. The latter which is short and subulate, rises from a depression in the centre of the disc. Immediately below it and united with the upper portion of the calyx is the ovary, which is 2-celled and contains many ovules. The lower end of the calyx (hypanthium) has a compressed form; it is solid but has its internal tissue far more porous than the walls. The whole calyx is of a deep rich brown, has a dull wrinkled surface, a dense fleshy texture, and abounds in essential oil which exudes on simple pressure with the nail. Cloves have an agreeable spicy odour, and a strong biting aromatic taste.
The varieties of cloves occurring in commerce do not exhibit any structural differences. Inferior kinds are distinguished by being less plump, less bright in tint, and less rich in essential oil. In London price-currents, cloves are enumerated in the order of value thus: Penang, Bencoolen, Amboyna, Zanzibar.
Microscopic Structure—A transverse section of the lower part of a clove shows a dark rhomboid zone, the tissue on either side of which is of a lighter hue. The outer layer beneath the epidermis exhibits a large number of oil-cells, frequently as much as 300 mkm. in diameter. About 200 oil-cells may be counted in one transverse section, so that the large amount of essential oil in the drug is well shown by its microscopic characters. The above-mentioned zone is chiefly made up of about 30 fibro-vascular bundles, another stronger bundle traversing the centre of the clove. The fibro-vascular bundles, as well as the tissue bordering the oil-cells, assume a greenish black hue by alcoholic perchloride of iron. Oil-cells are also largely distributed in the leaves, petals and even the stamens of Eugenia.
Chemical Composition—Few plants possess any organ so rich in essential oil as the drug under consideration. The oil known in pharmacy as Oleum Caryophylli, which is the important constituent of cloves, is obtainable to the extent of 16 to 20 per cent. But to extract the whole, the distillation must be long continued, the water being returned to the same material.