674 BOTANY AND PHARMACOGNOSY. 



Description. In irregular agglutinated tears or masses of 

 variable size ; externally rough and uneven, yellowish- or reddish- 

 brown, covered with a yellowish powder; brittle, the fractured 

 surface waxy, granular, oily, slightly mottled, somewhat trans- 

 lucent in thin pieces; odor balsamic; taste aromatic, bitter and 

 acrid. 



Myrrh forms a brownish-yellow emulsion when triturated with 

 water (distinction from other gum-resins) ; an ethereal solution 

 treated with bromine vapor becomes reddish (distinction from 

 East Indian myrrh) ; when moistened with nitric acid it becomes 

 purplish (distinction from false myrrh or bdellium) ; not more 

 than 70 per cent, is insoluble in alcohol. 



Constituents. A yellowish or yellowish-green, rather thick 

 volatile oil, 2.5 to 8 per cent., having the characteristic odor of 

 myrrh; resin, 25 to 40 per cent., composed of several constituents, 

 one of which yields protocatechuic acid and pyrocatechin ; gum, 

 about 60 per cent., consisting of a soluble and insoluble portion 

 and forming a mucilage that does not readily ferment ; a bitter 

 principle, sparingly soluble in water but soluble in alcohol ; ash, 

 5 to 10 per cent. 



The volatile oil of myrrh consists of cuminal (about i per 

 cent.), eugenol, meta-cresol, pinene, limonene, dipentene and two 

 sesquiterpenes. The acidity of old oil is due to free acetic and 

 palmitic acids. 



Adulterants. Myrrh is frequently admixed with gums and 

 other gum-resins, including several kinds of Bdellium which 

 are obtained from various species of Commiphora, and which are 

 characterized by not giving a purplish color with nitric acid. Of 

 these the following may be mentioned: African bdellium, 

 which occurs in yellowish-brown masses, that are reddish in trans- 

 mitted light and have a pepper-like odor and bitter taste ; Indian 

 bdellium, occurring in irregular, reddish-brown masses, covered 

 with minute spicules of resin, and having a terebinthinate odor 

 and an acrid taste; and opaque bdellium, which occurs in yel- 

 lowish, hard, opaque masses, with a faint odor and bitter taste, 

 and the alcoholic solution of which is colored black with ferric 

 chloride. Thin pieces of a bark are frequently present in opaque 

 bdellium. 



