There are a great many kinds of the aloe preserved in our green-houses and stoves. They are all natives of warmer climates; but of these there are only two that need be mentioned here, as the aloe kept by apothecaries, though of three kinds, is the produce of only two species. These two are the socotrine aloe-plant and the common aloe.
The socotrine aloe is a very beautiful plant; the leaves are like those of the pine-apple, eighteen or twenty inches long, prickly at the sides, and armed with a large thorn at the end. The stalk is half a yard high or more, naked at the bottom, but ornamented at top with a long spike of flowers; these are of a long shape and hollow, and of a beautiful red colour.
The socotrine or finest aloes are produced from this plant; the leaves are pressed gently, and the juice received in earthen vessels: it is set to settle, and then dried in the sun.
The common aloe is a very fine plant; the leaves are above two feet long, and an inch thick; they are dented at the edges and prickly, and have a very sharp thorn at the point. The stalk, when it flowers, is five or six feet high, and divided into several branches; the flowers are yellow streaked with green.
From the juice of the leaves of this plant are made the hepatic and the caballine aloes; the hepatic is made from the clearer and finer part of the juice, the caballine from the coarse sediment.
The socotrine aloes is the only kind that should be given inwardly; this may be known from the others, by not having their offensive smell. It is a most excellent purge; but it must not be given to women with child, nor to those who spit blood, for it may be fatal. The best way of giving it is in the tincture of hiera picra.