CORTEX ANGOSTURiE. ANGOSTURA BARK. 1 73 



bark of Strychnos Nnx vomica, which has been sold for 

 Angostura bark in Europe, comes in hard, thick, curved 

 fragments, the outer surface covered with a yellowish 

 cork marked with whitish warts and rust-colored patches. 

 The inner surface is gray and finely striated. A cross- 

 section shows near the surface a dense layer of whitish 

 stone cells forming a continuous layer not present in the 

 true bark. Oil cells and calcium oxalate raphides are 

 absent. The taste, owing to the presence of brucine 

 and strychnine, is very bitter without aroma. 



Brazilian Angostura, from Esemhekia febrifuga, is 

 dark brown on the inner surface, the fracture fibrous, 

 the taste bitter but not aromatic. It is distinguished 

 microscopically by the presence of an abundance of stone 

 cells, distributed in large groups throughout the entire 

 bark. 



The bark of Sternostomum acutatum, D. C, is dis- 

 tinguished by its smooth exterior surface, by the absence 

 of stone cells, and by the presence of ligneous fibres, in 

 very irregular groups. 



The bark of Alstonia scholaris is easily distinguished 

 by its peculiar rough, deeply marked, dark gray surface, 

 and microscopically by the presence of milk ducts, 

 the absence of oil cells, and the large lumens of the stone 

 cells. 



Chemistry. — The bark contains a yellowish, acrid, 

 volatile oil, 0.75 per cent, starch, resin, and three al- 

 kaloids — angosturine, Cj^^H^^Oj^, crystallizable, turning 

 red with sulphuric acid and green with sulphuric and 

 nitric acids, its salts yielding a blue fluorescent solution ; 

 galipein, Cj^jH^jNOj, crystallizing in white needles, yield- 

 ing soluble greenish-yellow salts; cusparin, Cj^Hj^NOj, 

 in greenish-yellow needles, yielding yellow salts. The 

 acetate and tartrate are soluble in water. Treated with 

 potash, cusparin splits up into another alkaloid and an 

 aromatic acid. 



