The roots have a fine odour; and, when immersed in ale or beer, are said to add considerably to the strength of the liquor. The leaves are sometimes eaten as a pot-herb, and in salads; and both the leaves and flowers are an excellent food for silk-worms.
59. BUCK-BEAN, or BOG-BEAN (Menyanthes trifoliata), is a common plant in shallow ponds; and is distinguishable by its leaves growing in threes, and its pink and white flowers being shaggy on their inner surface.
There is no British plant the flowers of which are more beautiful than those of buck-bean; and nothing but the difficulty of propagating it in dry ground could prevent its having a place in every garden. The leaves are intensely bitter, and are occasionally used in the Highlands of Scotland as a tea, to strengthen the stomach. The inhabitants of some parts of Sweden employ them in place of hops, to impart a bitter taste to ale; two ounces of them being considered equal in strength to a pound of hops. By some persons the leaves of buck-bean are smoked instead of tobacco; and different preparations of this plant have been found efficacious as a remedy against agues, and in scorbutic and scrofulous diseases, rheumatisms, and dropsy. There is an opinion that sheep, when compelled to eat of buck-bean, are cured of the rot. In Lapland it is said that the pounded roots, though very unpalatable, are sometimes converted into bread.
60. SCAMMONY is a concrete or dried juice obtained from the roots of a climbing plant of the convolvulus tribe (Convolvulus scammonia, Fig. 7,) which is cultivated in Asiatic Turkey, Syria, and Persia.
This plant is known by having arrow-shaped leaves, notched in a particular manner at the base, and each flower-stalk bearing two or three large and somewhat purplish white flowers.
The roots of the scammony plant are thick, black on the surface, white within, and full of an acrid milky juice, which, in a concrete state, is frequently used in medicine. To obtain it, the earth, at a certain season of the year, is removed from the upper part of the roots whilst they are growing, and the tops are cut obliquely. The juice flows from the wound into a small vessel sunk into the earth, at the lower end of the gash, to receive it. But, as each root furnishes only a very small quantity, the produce of several roots is usually mixed together for the greater convenience of being exposed to the sun and dried. Still, however, the quantity, thus obtained, is sometimes insufficient to supply the demand. In this case an addition is made to it by the pressure of juice from the leaves and stalks.
The best scammony is imported from Aleppo, in light, spongy, friable pieces, of shining blackish grey colour, which have a faint, unpleasant smell, and a bitterish, pungent taste. It is sometimes adulterated with flour, and sometimes even with sand or earth.
In its medical effects, scammony, when administered alone, is an efficacious, though violent purgative. But if triturated or ground down with sugar, almonds, or gum-arabic, its operation becomes sufficiently mild and safe.
61. JALAP is a dark-coloured root, which is usually imported, in transverse slices, from South America.
The plant that produces it (Convolvulus jalapa, Fig. 8) belongs to the convolvulus tribe, and has generally somewhat heart-shaped leaves, and flowers that are reddish on the outside, and dark purple or yellowish within.