12 SGROFHULARINE^, 



inclies long ; the fracture is short, the root very fragile and 

 light, and black internally ; it has no odour, and a very bitter 

 taste. 



Microscopic stmctt^re. — Tlie corky bark is made up of niraier- 

 ous rows of empty brick-shaped cells ; within this is a cellular 

 parenchyma of oblong brown cells, containing a little granular 

 matter"; next a dark brown line composed of wood cells^, form- 

 ing the boundary of the inner column of the root ; within this 

 several yery large bundles of dotted vessels arranged so as to 

 form a broken ring, which surrounds a central cellular paren- 

 chyma. 



Chemical composition. — A proximate analyas of this drug 

 showed the following percentage composition : — 



Wax 



1-06 



Bitter principle (Picrorhizin) , 14"96 



Picrorhizetin 3"85 



Organic acid ppt. by lead 3-54 



Glucose 11-53 



Cathartic acid, &e. (water extract) ... 9-33 



Substances dissolved by NaHO ...... 7*62 



Arabin bodies from crude fibre ...... 14'56 



Fibre 2400 



Moisture 5-73 



Ash 



The bitter principle is a erlucoside Picrorh 



3-82 



ater and alcohol, but almost insoluble in pure ether. It is 

 in reaction, is not precipitated from solution by lead salts 



olouring 



is absorbed by animal charcoal together with 

 matter that is present. It is best obtained by 

 exhausting the powdered drug with crude ether, and is left, 

 after the evaporation of the ether, in brown resinoid drops 

 which form^ ramified ciystals on standing. It is difficult to 



picrorhizin in a crystalline condition after heating 



lution in water. Any wax remoTcd by the crude 



ether can be separated from the dry extract by petroleum spirit, 



which has no solvent action on the bitter principle, 'i^he 



after 



^ 



