Astragalus Verus. Tragacanth, Gum Dragon.
Description: Natural Order, Leguminosae. A small shrub, native to Asia Minor, Armenia, and Northern Persia. Branches covered with imbricate scales and spines; leaves of eight to ten pairs of linear pinnae; flowers in axillary clusters of two to five, yellow, sessile, small; legume two-celled, dorsal suture turning inward. Two to three feet high. Several species and varieties are found.
The medicinal portion of this plant is a gummy exudation, generally obtained by making longitudinal incisions through the bark, at the lower part of the stem, during July and August. The gum dries in white, semi-circular flakes, and is gathered after three or four days. Changes in the weather give it a yellowish or reddish tinge, but without materially altering its qualities. It is insoluble in alcohol; cold water causes it to swell up in a large and dense gelatinous mass, but does not dissolve it; boiling water dissolves only a very small portion. It is without taste or smell.
Properties and Uses: The strained mucilage is occasionally used as a vehicle for exhibiting very active and dense powders. Its most common employment is as a basis for medicated troches and lozenges, for which its density well adapts it. Druggists generally use it as their label paste; for which purpose four drachms may be macerated in a pint of cold water, and more water added as required.
Pharmaceutical Preparations: I. Mucilage. Macerate five scruples of selected gum in ten ounces of boiling distilled water, for twenty-four hours; triturate, and strain by pressure through open muslin. In this form it is used in the preparation of troches and pills, and the exhibition of powders. A little rectified spirit may be added without causing any deposit.
II. Compound Powder. Select one ounce of the best flakes, dry them for several hours at a heat of 120 F, and pulverize them in a warm mortar. Triturate with this one ounce each of powdered starch and gum arabic, and three ounces of sugar. It makes a pleasant mucilage, when saturated with water, during the treatment of gastric and intestinal irritation, or for the exhibition of such powders as capsicum, myrrh, etc.
The Physiomedical Dispensatory, 1869, was written by William Cook, M.D.
It was scanned by Paul Bergner at http://medherb.com