TRAGACANTHA. -223 



with a rather fragrant fennel-like odour ; almost entirely soluble 

 in rectified spirit. 



Substances resembling Elemi : Assafoetidu, Galbanum, Ammo- 

 niacura, known by smell. 



Composition. Elemi is a mixture of a turpentine and several 

 resinous bodies. 



Preparation. 

 Unguentum Elemi. 1 in 5. 



ACTION AND USES. 



Elemi acts much like resin of turpentine, and is employed 

 in the ointment as a stimulant and disinfectant to sores and 



LEGUMINOS^:. 



Tragacantha TRAGACANTH. A gummy exu- 

 dation from the stems of Astragalus verus. and 

 possibly other species. Collected in Asia Minor. 



Characters. White or yellowish, in broad shell-like 

 slightly curved plates, tough and elastic, but rendered more 

 pulverisable by a heat of 120 Fahr. Very sparingly soluble 

 in cold water ; but swelling into a gelatinous mass, which is 

 tinged violet by tincture of iodine. After maceration in cold 

 water, the fluid portion is not precipitated by rectified spirit. 



Impurities. Other gums, and white lead. 



Composition. Tragacanth consists of two gums : bassorin. 

 33 per cent., comparatively insoluble in water, Ci 2 H 2o Oi , and 

 unfcrmentable ; a-nd a gum nearly identical with the arabin of 

 acacia (but precipitated by acetate of lead), 53 percent., soluble 

 in water. It also contains a little starch. 



Preparations. 



1. Mucilago Tragacanthae. 1 in 80. Dose, 1 fl.oz. or more. 



2. Pulvis Tragacanthse Composifos. Tragacanth. 1 ; Gum 



Acacia, 1 ; Starch, 1 ; Sugar, 3. Dose, 10 to 60 gr. 

 Tragapanth is also contained in Pulvis Opii Compositus. 



ACTION AND USES. 

 1. IMMEDIATE LOCAL ACTION AND USES. 



Internally, tragnc-dnth is demulcent. The mucilage may be 

 used as a vehicle for active substances in linctuses for pharyii- 



