480 _ LEGUMINOSA. 
Tragacanth of Westerncommerce. Tragacanth has been known — 4 
from a very early period, and Theophrastus and Dioscoridel q 
were probably familiar with the plant from which it was” % 
obtained, as the latter writer describes it very correctly. The q 
later Greek physicians were all acquainted with the drug, as ’ 
well as Masih, Ibn Sina, and the other Arabian writers. Haji 3 
Zein, A. D. 1368, describes its uses almost in the words of — 
Dissosvidess ; he calls it Katira, the gum of the tree called Katéds _ 
this name the Arabs have converted into Kathiré. According — 
to the Persian Burhan, the Arabic name for the tree is Miswik- — : 
el-Abbas. The author of the “‘ Makhzan-el-Adwiya”’ says that q 
the Persian name of the tree is w»S (Kon), a name which Dr. q 
Aitchison found to be current among the peasantry of the 
Hari-rud valley for the second species placed at the head of this 
article. Formerly the imports of Tragacanth into India were 
insignificant, and only sufficient to meet the requirements | of & 
few Persian physicians practising in the country, with whom it 
is a favourite pectoral, and demulcent in urinary affections. Now» 4 
however, it is making its appearance in the Bombay market in — 
large quantities, and of a superior quality to that formerly 
- imported, for the purpose of export to Europe. In modern : 
medicine Tragacanth is chiefly valued for its mechanical pro-— 
perty. of suspending insoluble powders in mixtures and for a 
= pire firmness to lozenges and pill masses. 
Secretion: —It has been shown by H. von Mohl and by 
é Wigand that T ragacanth is produced by metamorphosis of the — 
cell membrane, and that it is not simply the dried juice of the — 
‘plant. The stem of a gum-bearing Astragalus, cut transversely, 
“exhibits concentric apnual layers which are extremely tough 
and fibrous, easily tearing lengthwise into thin filaments. : 
These inclose a centra! column, radiating from which are nu-_ ; 
merous medullary rays, both of very singular structure, for — 3 
‘instead of presenting a thin-walled parenchyme, they appeat — , 
sabetance ie se const nto rie m mu il : 
