The Senega Tree.
Senica.
A tree frequent in the East, and named from a gum which it affords, and which is brought in great quantities into Europe. The tree is large and spreading; its trunk is covered with a rough bark, its branches with a smoother, of a pale brown, and they are very full of thorns.
The leaves are large, and they are composed of many smaller, set in pairs, very beautifully and evenly about a common rib, with an odd one at the end of each rib: they are oblong, and of a beautiful green. The flowers are white, and of the shape of a pea blossom; the fruit is a large and flat pod, jointed or divided into several parts, with seeds in them; the tree is of the acacia kind, in many things very like that which produces the gum arabic, and the gum which is obtained from it is in the same manner very like that.
This gum is the only product of the tree heard of in medicine, and this is not much. It is brought over, however, in great quantities, for the dyers use a great deal of it. It is in large lumps, of the bigness of an egg; rough on the surface, but glossy and smooth when broken, and of a pale brown colour. It is as easily and entirely dissolved in water as gum arabic, and has the same virtues. It is very seldom called for by name in medicine, but it is nevertheless often used, for the druggists have a way of breaking the lumps to pieces, and putting them among the gum arabic; they may be distinguished by their brown colour, the true gum arabic being white, or yellowish, if coloured at all, and never having any brown in it: some pick these brown pieces out; but, upon a separate trial, they are found to be so perfectly of the same nature, that it is a needless trouble.
