ON THE EXAMINATION OP BALSAM OF COPAIBA. 303 
in its consistence, more thickened by age, and when agitat- 
ed with a solution of caustic potash, the latter caused the 
separation of a transparent soap, with greater difficulty, 
and only after the lapse of several days. It was some- 
times even necessary to employ a slight degree of heat, so 
that it has frequently been looked upon as adulterated, 
notwithstanding its complete solubility in alcohol. This 
last idea originated at a time when balsam of copaiba was 
at a high price, and, as old castor oil was to be obtained at 
a much cheaper rate, it was frequently employed to adul- 
terate the balsam. This adulteration only became manifest 
by the semi-fluid residuum left behind, after the evapora- 
tion of the pure essential oil, and the pure thickened bal- 
sam, considered as adulterated by a mixture of castor oil, 
was that alone which justified the suspicion, by this 
method. 
Latterly, the balsam, principally brought from Mexico 
and the West Indies, frequently appears in commerce in a 
very fluid state, and occasions the complaints in question. 
The cause of this difference can only be attributed to its 
being newer, or less dense, or to adulteration, but in most 
cases to the first of these causes. 
M. Gerber, in 1829, examined various specimens of bal 
sam of copaiba ; he found — 
M. Stockhardt, last year, directed our attention to an 
extremely liquid balsam which had all the appearance of 
good balsam ; two specimens of which, obtained from dif- 
ferent sources, left, after the complete evaporation of the 
essential oil, the one 42, the other 43.5 of brittle yellow re- 
sin ; while, according to M. Gerber, the resent balsam yield- 
Recent balsam. Old balsam. 
Essential oil 
41.00 
51.38 
2.18 
5.44 
31.70 
53.68 
11.13 
4.10 
Hard yellow resin 
Soft brown resin 
Water and loss . 
