MYRRH 



479 



The student should observe 



(a) The unctuous, granular (not uniform or vitreous) fracture, 



(b) The translucent (not opaque) appearance of thin fragments, 



(c) The aromatic, bitter taste. 



The taste and the violet colour-reaction are, perhaps, the most 

 characteristic features of myrrh. 



FIG. 242. Myrrh. Section of a portion of bark, probably of Commi- 

 phora Myrrha. P, outer portion (bark) in which layers of 

 sclerenchymatous cells, st, alternate with thin-walled cells, d ; 

 p, bast parenchyma ; b, bast fibres ; m, medullary ray ; o, oleo- 

 resin ducts containing a granular secretion (myrrh) ; 0, tissue 

 breaking down to form a cavity filled with the secretion. 

 Magnified 280 diam. (Vogl.) 



Constituents. Myrrh consists of a mixture of resin, gum, and 

 volatile oil. The latter can be obtained by distillation with water 

 to the extent of 2-5 to 6'5 per cent. (Schimmel). The resin occurs 

 in amounts varying from 25 to 35 per cent., the remainder of the 

 drug consisting of gum, moisture, and various impurities. 



