478 GUM-RESINS 



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MYRRH 

 (Myrrha) 



Source, &C. Myrrh is a gum-resin obtained from the stem of Ccm- 

 miphora Myrrha, Holmes, and probably other species (N.O. Bur- 

 seracece). It is collected chiefly in Somaliland (in the north-east 

 of Africa), brought down to the coast and sent to Aden, whence it is 

 shipped to Europe, either direct or via Bombay. Some myrrh is 

 said also to be collected in the south of Arabia. Several other species 

 of Commiphora are found in Arabia and north-eastern Africa yielding 

 gum-resins that more or less resemble the official myrrh in appear- 

 ance and odour. 



These plants are shrubs or small trees, and, like most other plants 

 belonging to the same natural order, they contain numerous schizo- 

 genous ducts in the bark, in which an oleo-gum-resin is secreted. 

 In the case of the species from which the official myrrh is derived 

 the tissue intervening between the ducts frequently breaks down 

 and thus lysigenous cavities of considerable extent are produced 

 which, together with the ducts that remain intact, are filled with a 

 granular secretion. When the bark is wounded, therefore, the secre- 

 tion is discharged in considerable quantity. It is first yellowish 

 white and fluid, but soon hardens to a firm, reddish brown mass 

 which constitutes the commercial drug. The secretion also exudes 

 from fissures that are formed in the bark by natural causes ; indeed 

 the bulk of the drug is said to be naturally exuded. 



It not unfrequently contains other gums and gum-resins from 

 which it is freed by hand picking. 



Description. Myrrh occurs in irregular rounded tears, or lumps 

 composed of agglutinated tears, varying in size from small grains up 

 to masses nearly as large as the fist, pieces about the size of a walnut 

 being of common occurrence. They have a reddish yellow or 

 reddish brown colour and a rather rough, dull, dusty surface. 

 They break fairly easily, the fractured surface having a rich brown or 

 reddish brown colour and translucent, unctuous, granular appearance, 

 often exhibiting whitish spots or veins ; thin splinters are trans- 

 lucent or almost transparent. The drug has an agreeable aromatic 

 odour and an aromatic, bitter and acrid, but not unpleasant taste. 

 Triturated with water it yields a yellowish emulsion. If one gramme 

 of the coarsely powdered drug is shaken for a few minutes with 

 10 c.c. of ether and 2 c.c. of the ethereal .solution allowed to 

 evaporate to a thin film in a small porcelain dish, the residue is 

 coloured instantly deep violet-black by the vapour of bromine, or 

 violet by nitric acid diluted with an equal volume of water. The 

 resinous film obtained by evaporating tincture of myrrh will also 

 yield similar reactions. 



