ASTRAGALUS VERUS.— TRUE ASTRAGALUS. 
Class XVII. DIADELPHIA.— Order III. DECANDRIA. 
Natural Order, LEGUMINOS.E. THE PEA TRIBE. 
This species of Astragalus is a native of the north of Persia, where it is called Kurn, flowering in July and 
August ; we are indebted to Oliver for the discovery of this plant, which furnishes the Gum Tragacanth of 
commerce. 
This is a low tree, seldom exceeding three feet in height ; the stem is about an inch in diameter ; the 
branches numerous and crowded together, and covered with imbricated spines and scales formed of the pe- 
tioles of the preceding year ; the leaves are pinnate, consisting of six or eight pairs of leaflets ; the pinnae 
are nearly opposite, villous, stiff 1 , and pointed ; the flowers are small and of a yellow colour, and arise from 
the axilla of the leaves ; the calyx is divided at the brim into five pointed segments ; the corolla is of the 
papilionaceous kind. 
Tournefort tells us, that the naked hillocks of Mount Ida in Candia produce this plant abundantly. 
The gum exudes spontaneously towards the end of June and in the following months, during which period 
the nutritious juice of the plant, thickened by the summer heat, bursts most of the vessels in which it is 
confined. This juice coagulates in threads, which make their way into the pores of the bark, through which 
being pushed forward by fresh juice they issue forth, and are at length hardened in the air, either in irregular 
lumps, or in long vermicular pieces bent into a variety of shapes. The best sort is white and semi-trans- 
parent, dry, but somewhat soft to the touch. It is extremely different in many of its properties to gum 
arabic ; one part of this diffused in one hundred parts of water affords a fluid of the same consistency as one 
part of gum arabic dissolved in ten parts of water. Water is, however, but an imperfect solvent to it, not 
forming the same intimate union with it as with other gums. When tragacanth is put into water it slowly 
imbibes a great quantity, swells into a large volume, and forms a soft but not fluid mucilage. On the addi- 
tion of more water, and if the mixture be agitated, the gum will be more generally diffused throughout the 
liquor, which will appear turbid. If left at rest the mucilage will again separate and subside ; the super- 
natant water appearing limpid, and holding only a very small portion of the gum. 
This is more costly than gum arabic or Senegal, but its employment is highly beneficial in topical dye- 
ing, when the mordant is prepared with nitrous acid ; since other gummy solutions are coagulated by the 
application of this active alterative. 
In 1830 the quantity of tragacanth retained for home consumption was 29,725 lbs. It is admitted on 
a duty of Is. per lb. ; its price being from £16 to £18 per cwt. 
Sensible and Chemical Properties. Gum Tragacanth when good is inodorous, and as it dis- 
solves in the mouth imparts a slight bitter taste : the best gum is semi-transparent, and of a clear whitish 
colour, and in small, thin, wrinkled, vermicular pieces or lumps ; the larger lumps are of a yellowish colour, 
and more bitter to the taste. This gum differs from all other known gums, in giving a thick consistence to 
a much larger quantity of water, and at the same time being much more difficult of solution, or rather, dis- 
solving only imperfectly, unless triturated after digestion with a larger portion of water ; for although the 
liquor looks turbid, on standing the mucilage subsides, the water on the surface retaining little or none of 
the gum. If the water be acidulated with any of the mineral acids, a small portion of the gum becomes dis- 
solved. Tragacanth is reduced to powder with much difficulty, unless thoroughly dried. According to 
Neumann, it gives nothing over in distillation, either to water or alcohol ; it is also insoluble in alcohol or 
ether. The mucilage is precipitated by the sulphate of copper, superacetate of lead, and oxymuriate of tin ; 
but not by silicated potass or the oxysulphate of iron : in these circumstances the mucilage of tragacanth 
differs from that of gum arabic. 
Mr. Field, in his Treatise on Colours, says that, “ Tragacanth is of excellent use when colours are re- 
quired to lie flat, or not bear out with gloss, and also when a gelatinous texture of the vehicle is of use to 
preserve the touch of the pencil and prevent the flowing of some colours ; or to fix drawings executed with 
the black-lead pencil.” 
Medical Properties and Uses. — Gum tragacanth is demulcent, hence it is very useful for allaying 
tickling coughs and sheathing the fauces in catarrhal affections ; and for these purposes (from its great 
viscidity) it is preferable to gum arabic : it is seldom given alone, being generally combined with more 
powerful medicines, more especially in the form of troches, for which purpose it is very well adapted. Tra- 
gacanth may be taken in powder, from ten grains to one drachm or more, in any suitable vehicle. 
Off. The Gum. 
Off. Pp. Mucilago Astragali Tragacanthse, E. D. 
Pulvis Tragacanthm Compositum, L. 
A superstitious veneration for particular flowers — in other words, flower-worship — is an ancient, and, 
in some respects, a poetical variety of the depraved systems of religious homage into which certain of the 
human family have fallen. It is to be traced ages back in the religious observances of the Hindoos, and 
among the more enlightened Chinese: it formed an important part of the mysteries of Egyptian idolatry; 
and it is remarkable that the past and present monuments of the Mexicans exhibit, and with great promi- 
