346 
SELECTED ARTICLES. 
The following are the characters of the two barks: 
Bark of the Swietenia, (true rohun,) gray externally, sub- 
stance red, consistence soft, texture flexible, taste slightly bit- 
ter and austere, powder coarse and red, aqueous infusion red, 
colour of cinchona, not affected by nitric acid. 
Bark of the Strychnos nux vomica^ gray externally, deep 
brown or black internally, sometimes covered with lichens of 
a rust colour, friable, taste bitter, insupportable, powder gray, 
aqueous infusion yellow; the bark assumes a blood red colour 
when touched with nitric acid.* 
♦ The bark, of which mention is here made, appears to be the false 
angustura itself, as it presents the same characters. It is, moreover, 
known, that false angustura is the bark of a Strychnos (according to M. 
Virey,) near to the S. nux vomica^ if it is not derived from this plant. As 
to the substance determined by Dr. O'Shaugnessy to be strychnia, it appears 
to us rather to be brucia, which is more easily confounded, from its ap- 
pearance, with quinia, than it is likely strychnia would be. 
