A pale yellow clear oil is obtained from the seed of Dolichos biflorus(?). Oil is also expressed in India from the seed of the Argemone mexicana, which is used for lamps and in medicine; and from the seeds of the cashew nut (Anacardium occidentale), from Sapindus marginatus, and the country walnut (Aleurites triloba.) The fruit of the Chirongia sapinda, (or Buchanania latifolia,) yields oil. From the seeds of the Pongamia glabra, or Galidupa arborea, a honey brown and almost tasteless oil is procured, which is fluid at common temperatures, but gelatinises at 55 degrees.
Other sources of oil are the Celastrus paniculatus (?) Balanites Egyptictca and the saul tree (Shorea Robusta).
THE CANDLE-TREE or PALO BE VELAS, (Parmentiera cereifera, Seemann.)—This tree, in the valley of the Chagres, South America, forms entire forests. In entering them a person might almost fancy himself transported into a chandler's shop. From all the stems and lower branches hang long cylindrical fruits, of a yellow wax color, so much resembling a candle as to have given rise to the popular appellation. The fruit is generally from two to three, but not unfrequently four feet long, and an inch in diameter. The tree itself is about 24 feet high, with, opposite trifoliated leaves, and large white blossoms, which appear throughout the year, but are in greatest abundance during the rainy season. The Palo de Velas belongs to the natural order Crescentiaceae, and is a Parmentiera, of which genus hitherto only one species, the P. edulis, of De Candolle, was known to exist. The fruit of the latter, called Quauhscilote, is eaten by the Mexicans, while that of the former serves for food to numerous herds of cattle. Bullocks especially, if fed with the fruit of this tree, guinea-grass, and Batatilla (Ipomœa brachypoda, Benth.), soon get fat. It is generally admitted, however, that the meat partakes in some degree of the peculiar apple-like smell of the fruit, but this is by no means disagreeable, and easily prevented, if, for a few days previous to killing the animal, the food is changed. The tree produces its principal harvest during the dry season, when all the herbaceous vegetation is burned up, and on that account its cultivation in tropical countries is especially to be recommended; a few acres of it would effectually prevent that want of fodder which is always most severely felt after the periodical rains have ceased.—("Hooker's Journal of Botany.")
CINNAMON SUET is extracted by boiling the fruit of the cinnamon. An oily fluid floats on the surface, which on cooling subsides to the bottom of the vessel, and hardens into a substance like mutton suet. The Singhalese make a kind of candles with it, and use it for culinary purposes. It emits a very pleasant aroma while burning. According to the analysis of Dr. Christison, it contains eight per cent, of a fluid not unlike olive oil; the remainder is a waxy principle.
CROTON OIL is obtained by expression from the seeds or nuts of Croton Tiglium, an evergreen tree, 15 to 20 feet in height, belonging to the same order as the castor oil plant, producing whitish green flowers, and seeds resembling a tick in appearance, whence its generic name. It is a native of the East Indies. 100 parts of seeds afford about 64 of kernel. 50 quarters of croton nuts for expressing oil were imported into Liverpool from the Cape Verd Islands, in 1849.
The Croton Tiglium grows plentifully in Ceylon, and the oil, if properly expressed, might be made an article of trade. The best mode of preparing it is by grinding the seeds, placing the powder in bags, and pressing between plates of iron; allow the oil to stand for fifteen days, then filter. The residue of the expression is triturated with twice its weight of alcohol, and heated on the sand-bath from 120 to 140 degs. Fahrenheit, and the mixture pressed again. In this step the utmost caution is necessary in avoiding the acrid fumes. One seer of seed furnishes by this process rather more than eleven fluid ounces of oil, six by the first step, and five by alcohol.
The oil acts as an irritant purgative in the dose of one drop. In large doses it is a dangerous poison. When applied externally it produces pustules.
In 1845, eight cases of croton oil and six cases of the seed were exported from Ceylon.
Other species of Croton, as C. Pavana, a native of Ava and the north-eastern parts of Bengal, and C. Roxburghii, yield a purgative oil. The bark of C. Eleuteria, C. Cascarilla, and other species is aromatic, and acts as a tonic and stimulant. It forms the cascarilla bark of commerce already spoken of. When bruised, it gives out a musky odor and is often used in pastilles.
The oil obtained from the seeds of Jatropha curcas, a native of South America and Asia, is purgative and emetic, and analagous in its properties to croton oil. It is said to be a valuable external application in itch. In India it is used for lamps.