(From to sharpen). The Egyptian Thorn, or Binding Bean-tree.
Several species are enumerated by botanists; but the two sorts used in medicine are,
1. Acacia Vera; called, by Caspar Bauhine, acacia foliis scorpioidis leguminosae; and, by others, acacia veravel, spina Egyptiaca. It is the mimosa Nilotica. Sp. Pi. L. 1506.
The true acacia, or Egyptian thorn, produces the true gum arable. See Gummi arabicum. It is remarkable that the leaves and flowers of the black thorn are purgative, though the juice from the other part is astringent.
The acacia used in medicine, and brought from Egypt, is a mild, subastringent, gummy substance. We receive it in roundish pieces, wrapped up in bladders; and it is of a blackish brown colour outwardly, but of a tan colour inwardly; of a hardish consistence, but not quite dry. Lcmery says, that "it is made by expression out of the fruit of the Egyptian thorn, either ripe or unripe: from the ripe fruit there is a black juice, from the unripe a red or yellow one, and of a sweet scent; and that this last is what is intended by Dioscorides." It hath no smell: applied to the tongue it soon softens; is of a moderately rough but an agree able taste, which is followed by a sweetishness: it. totally dissolves in water; so that any fraudulent addition may be discovered: rectified spirit dissolves but a small proportion, though vegetable astringents generally give out their virtue to spirit of wine as well as to water.
The Egyptian acacia is now seldom used as a medicine, but is superseded by the terra japonica, the production of a similar plant belonging to the same genus, whose appellation, kate or kataa, is not very different from that of the substance we are now considering. It was used in all cases of laxity and excessive discharges; indeed in every disease where astringents are indicated.
2. Acacia Germanica, called also Prunus Syl-vestris, Lin. Sp. Pi. 681. It is the prunus spinosa; or prunus sylvestris spinosa, foliis lanceolatis pe-dunculis solitariis, of Linnaeus. German acacia, or the German black-thorn, or sloe-tree.
The German acacia is the inspissated juice of the German wild sloes; it is of the same nature as the true sort; but in England the inspissated juice of unripe sloes of our own growth is the general substitute: it is harder, heavier, darker coloured, being almost black, and sharper tasted than the true sort. Dose 3ss.