194 
TESTS OP THE PURITY OF BALSAM OP COPAIBA. 
tory, of examining a sample of copaiba, with the view of 
estimating its purity and value as a therapeutic agent, is, 
first, to resolve it into its proximate constituents, and then 
to examine these separately, with reference to their physi- 
cal and chemical characters. The volatile oil is generally 
considered to be the principal, if not the only constituent of 
copaiba, which possesses any medicinal activity. This may 
be separated by distilling the copaiba with water, and its 
physical characters are so well marked, that it is difficult 
to conceive an adulteration that would not be readily detect- 
ed. The resin would of course be at the same time sepa- 
rated by the above process of distillation, and the consis- 
tence and other characters of this part of the constituents of 
the copaiba will afford the best means of judging of the pre- 
sence or absence of any non-volatile impurities. 
The proportion of volatile oil, in different specimens of 
copaiba met with in commerce, is in some cases as low as 
30 ; in others as high as 60 per cent. The specimens No. 
1 and 2, alluded to in the foregoing experiments, contain 
nearly 60 per cent, of volatile oil; they are therefore un- 
usually rich in the most active constituent of the copaiba- 
This volatile oil has the same ultimate composition as the 
oil of turpentine, with which it closely coincides in the action 
produced by most chemical agents ; but its taste, smell, and 
other physical characters, afford means of distinguishing it 
from that or any other substance with which it is likely to 
be mixed. 
The proportions of resin, in different specimens of copaiba, 
also vary to about the same extent as those of the volatile 
oil, the quantity being greatest where the quantity of oil is 
smallest, and vice versa. The resinous part of copaiba dif- 
fers but little from common resin, obtained from turpentine. 
It is considered to possess but little medicinal activity, pro- 
bably not more than common resin. — Pharm. Jour, 
