72 VEGETABLE DRUGS WITHOUT ORGANIC STRUCTURE. 



Splintery fracture, small pieces of the splinters being 

 transparent. 



Myrrh powders with difficulty. Rubbed up with water 

 it produces an emulsion which shows globules of oil, resin, 

 and pieces of bark. 



The odor is agreeable and characteristic. It can be 

 chewed and the taste is aromatic, later bitter to acrid. 



Fig. 7. — Myrrha. 

 Cross-section of bark of Balsamea Myrrha: sb, Obliterated sieve 

 tubes; st, bast-fibers; /, 5, coloring-matter and secretory cells; oe, oil and 

 resin passages; rs, medullary rays; sc, stone cells (Tschirch). 



Dark colored pieces, and more particularly those that 

 are soluble in water, should be rejected. 



Chemistry. — In alcohol and ordinary solvents myrrh 

 is but slightly soluble. In hot water it gives up a bitter 

 principle, and from 40 to 60 per cent, of gum. In ad- 

 dition it also contains 4 to 5 per cent, ethereal oil and 25 

 to 30 per cent, resin; soluble in alcohol, which solution 



