The African modes of manufacture are still more primitive. In Cape Colony, the operator spreads a goat-skin in a shallow dished hollow, in dry ground, and lays the leaves on it in a circle, the cut ends inwards. Additional layers are piled up in the same way, the ends always projecting so as to drip into the central hollow. When the skin is nearly full of juice, its contents are emptied into an iron pot, and there boiled in the most careless manner. The industry is almost confined to the Bastaards and Hottentots, who adopt it only when more profitable work fails. In Natal, the process much resembles that in vogue at the Cape, but it is better conducted. The leaves are sliced obliquely, and the juice is left to exude in the sunshine ; it is then boiled down in iron pots, and stirred as it thickens, to prevent burning. While still hot, it is poured into wooden cases, ready for shipment. The preparation is performed by Kaffir's, employed by British and Dutch settlers. In Socotra, aloes forms the most important vegetable production. The plant flourishes in a wild state on the sides and summits of the limestone mountains, at elevations of 500-3000 ft. above the plains. The plant prefers parched and barren spots, and is most abundant on the western side of the island. Formerly the whole island produced aloes, the cultivation of which was monopolized and farmed out by the Sultan ; now everyone is free to gather the plant, without payment of any impost. The leaves are plucked at all seasons, placed in a skin, to preserve the escaping juice, and thus conveyed to the ports of Tamarida and Colesseab. The product is much deteriorated by the careless manner of the collecting and packing. It arrives at Zanzibar from Socotra, in a very soft state, packed in goat-skins ; it is there transferred to wooden cases, in which it concretes, for shipment. The skins are washed, and the aloetic liquor is evaporated, to avoid waste.
Commerce.—(1) Socotrine (Bombay, East Indian, or Zanzibar) aloes, called also "Hepatic," when opaque and liver-coloured, is imported in kegs and tin-lined boxes via, Bombay, the Zanzibar aloes usually in monkey-skins ; its colour is dark reddish-brown ; its odour resembles myrrh or saffron. It is usually soft in the interior, but hardens by keeping, losing about 14 per cent. in weight. When quite liquid, it is known as "liquid Socotrine aloes," or "aloe juice," and is often sour and spoilt. The so-called " Mocha " aloes is a very inferior, dark, foetid variety, brought to Aden from the interior of Arabia. The imports into Bombay in 1876-7, were 204 cwt.; in 1877-8, 634 cwt. The Socotrine aloes is valued at about 25 rupees a cwt.; the black, at 10 rupees. (2) Barbadoes aloes is hard and dry, chocolate-coloured, and with dull waxy fracture ; its odour is distinct from, and more disagreeable than, that of the Socotrine drug. It is imported in boxes and gourds, containing 10-40 lb. or more. " Capey Barbadoes " is the same drug with smooth glossy fracture ; by keeping, it passes into the common sort. The exports from Barbadoes, in 1871, were 956 cwt. Curacoa aloes is distinguished from the preceding by its odour. It comes to us via.
Holland, in boxes of 15-28 lb, Barbadoes aloes is worth about 60-190s. a cwt. (3) Cape aloes is distinguished by brilliant conchoidal fracture, and a peculiar odour resembling those of other varieties added to a sourish taint. The degrees of brilliancy of the fracture and of the colour of the powder are a basis for its division into several qualities. The exports from Port Elizabeth, in 1878, were 73,214 lb., valued at 658/. ; in 1877,3259 lb., valued at 40/. The approximate prices in the home market are—good, 40-42s. a cwt.; inferior, 36-39s. a cwt. This variety is not admitted into English medicine, but is esteemed on the Continent, and chiefly consumed there. (4) Natal aloes is greyish-brown, mostly opaque, like the hepatic, and quite unlike the Cape drug, except in odour. It is prepared in the district between Pietermaritzburg and the Quathlamba mountains, partioularly in the counties of Mcoi River and Umvoti, at altitudes of 2000-4000 ft. The exports commenced in 1869 with 38 cwt. ; in 1872, they were 501 cwt. The approximate market price is 48s. a cwt. It yields a pale greenish-yellow powder. (5) Hepatic aloes was a term originally applied to the opaque liver-coloured kind of Socotrine aloes ; but Natal aloea is often sold' under this name. True bepatio aloea has an odour like Socotrine, and gives an orange powder. The prico is about 40-80s. a cwt.
Ammoniacum.—The hardened milky juice of the stem of Dorema Ammoniacum is administered as an expectorant, and used in some plasters. (See Resinous Substances.) Angostura, Cusparia, or Carony (Fs., Ecorce d'Angusture de Colorable; GER., Angostura Rinde).—The bark of Galipea Cusparia (G. officinalis, Bonplandia trifoliata, Cusparia trifoliata) is a valuable tonio in dyspepsia, dysentery, and diarrhoea, but is going out of use. The tree is a native of Venezuela, and ie said sometimes to attain a height of 70-80 ft.. but generally doea not exceed 12-15 ft. It is abundant on the mountains of San Joaquin de Caroni, in N. lat., near Cumaua, and in the districts of Tumeremo, Uri, Alta Gracia, and Cupapui, eastward of the Caroni river, and near the Orinoco. The bark occurs in piecea of various sizes, either flattish or in quills. Ita fracture is brittle and resinous, its flavour is bitter, and its odour musty and nauseous. Its local names are Orayura, Quina de Caroni, and Cascarilla del Angostura ; it is said to be a valuable remedy for the bilious fevers of the country ; and, in a bruised state, is used by the natives for intoxicating fish. Very little of it is exported directly ; it passes principally via Trinidad, where it is packed in cases for export. The bark ie sometimes confounded with that of the closely allied Esenbeckia febrifuga (Evodia febrifuga) of Brazil, which is distinguished by ita dark inner surface and by being non-aromatic. Copalchi bark has also been sold for it in this country. It has a pleaaantly aromatio taste, and a whiter ooat, under which the bark is marked with minute pits. Nux vomits bark has occasionally bean found mixed with this drug ; it is not aromatic, and can only be distin guished by an expert. The value of Angostura bark is about 3-4s. a lb.