MYRRH 381 



narrow. Calcium oxalate Is secreted in the form of rosette aggre- 

 gates or solitary crystals (Fig. 167). Glandular and non-glandular 

 hairs are of a number of specific forms. 



MYRRHA. Myrrh. The dried gum-resin from the stem of 

 Commiphora abyssinica and C. Schimperi (Fam. Burseracese), 

 rather large shrubs indigenous to northeastern Africa (chiefly Somali 

 Land) and southern Arabia. The gum-resin exudes naturally or 

 from incisions made in the bark; it is first of a yellowish color, but 

 soon hardens, becoming darker, and is then collected. There are 

 two principal commercial varieties of Myrrh, the one known as 

 African or Somali Myrrh, and the other as Arabian or Yemen Myrrh, 

 the former being considered the better of the two. 



Description. In irregular, agglutinated tears or masses varying 

 in size; externally rough and uneven, yellowish- or reddish-brown, 

 covered with a yellowish powder; brittle, the fractured surface waxy, 

 grandular, oily, slightly mottled, somewhat translucent 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 bromin 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 65 per 

 cent is insoluble in, alcohol. 



Inner Structure of the Bark. (Fig. 167.) 



Powder. In glycerin mounts the powder shows yellowish or 

 yellowish-brown irregular fragments made up of a grayish matrix, 

 containing yellowish or yellowish-brown oil globules, a few frag- 

 ments of lignified tissues consisting of either sclerenchymatous 

 fibers, or of small groups of stone cells, the individual cells of the 

 latter having very thick, porous walls and being from 0.015 to 

 0.050 mm. in length; occasional starch grains from 0.010 to 0.035 

 mm. in diameter and varying from spheroidal to somewhat pear- 

 shaped grains. 



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 soluble and insoluble portions, which 

 forms 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 cuminol (about 1 per cent), 

 eugenol, meta-eresol, pinene, limonene, dipentene and two sesqui- 



