107. SOCOTRINE ALOES are the dried juice of a large species of aloe (Aloe perfoliata, Fig. 38) which grows in great abundance in the island of Socotra, near the mouth of the Red Sea.
The leaves are sword-shaped, fleshy, smooth, full of juice, of bluish-green colour; and beset at the edges with strong spines. The flower-stems rise to the height of three or four feet, are smooth, erect, and have at the top a spike of flowers of purple or reddish colour, the stamens of which have oblong orange-coloured anthers.
The true Socotrine aloes are imported into this country wrapped in skins; and when pure have a bright surface, and are in some degree pellucid. In the lump they have a yellowish red colour, with a purplish cast; and, when reduced to powder, are of a golden yellow. Their taste is bitter and disagreeable, but somewhat aromatic; and their smell is not unpleasant.
Barbadoes aloes, common aloes, or hepatic aloes, are the dried juice of a variety of the Socotrine aloes, which is cultivated in Barbadoes and Jamaica. Of this we import three kinds: one in gourd shells; an inferior kind, in pots; and another, still worse, in casks.
In the cultivation of aloes it is requisite that the plants should grow for two or three years before the juice is procured from them. The operation of collecting the juice is performed in different ways. Dr. Browne tells us that labourers go into the field with knives and tubs; and that cutting off the largest and most succulent leaves close to the stalk, they immediately put them into the tubs in an upright position, that the liquor may drain from the wounds. When this is nearly all discharged, they take the leaves out singly, and clear them of any juice that may adhere to them; and the liquor is then put into shallow flat-bottomed vessels, and dried gradually in the sun, until it acquires a proper thickness to be poured out or ladled into the gourd shells which are to contain it. What is thus obtained is called Socotrine aloes, and is the clearest and most valuable of any. An additional quantity of juice is obtained by pressing the leaves.
In some places the plants are pulled up by the roots, and, after having been carefully cleansed from earth or other impurities, they are sliced and cut in pieces, into small hand-baskets or nets. In these the pieces are boiled, for a little while, in water, by which the juice is extracted; and successive basketfuls are boiled in the same liquor, until it becomes thick and of dark colour. The fluid part is subsequently evaporated, and what remains is put into gourd shells for sale.
Other methods of inspissating or drying the juice are to pour it into bladders left open at the top, and suspended in the sun; or to place it in broad shallow trays of wood, pewter or tin, exposed to the sun every dry day, until the fluid parts are exhaled, and a perfect resin is formed, which is then packed up for sale.
There is a kind called Caballine or horse aloes, which has a rank and unpleasant smell, but in taste is not much more disagreeable than either of the others. In its properties it agrees nearly with hepatic aloes, but it is chiefly employed by farriers in horse medicines.
The medical properties of aloes have long been known and established: and their extensive application in medicine is, perhaps, the best proof that can be adduced of their utility. In the arts aloes are, in several respects, useful. But, particularly, the leaves of the Socotrine aloes afford a beautiful violet colour which does not require the aid of any mordant to fix it; the same also is capable of being formed into a fine transparent colour for painting in miniature.
108. The GREAT, or AMERICAN ALOE (Agave Americana), is a large plant, the leaves of which are thick, fleshy, and spinous at the edge, and the stem branched and of great height.