OBSERVATIONS ON COPAIBA. 
291 
it boils at 473° F. but undergoes a slight alteration unless 
oxygen is excluded ; it is very soluble in anhydrous alcohol, 
but much less so in that of officinal strength (.S35). It is the 
cause of the peculiar penetrating odor of copaiba, and has a 
biting extremely disagreeable persistent taste. Durand first 
ascertained it to be a hydro-carbon by noticing its indiffer- 
ence towards potassium, which keeps well in it. It is gradu- 
ally resinified by exposure to the air. 
The resinous portion of copaiba consists of two distinct 
substances : one of these is a strong resinous acid to which 
the name of copaivic acid has been given. The other is 
neutral, incapable of uniting with bases, has a perma- 
nently soft consistence, is soluble in anhydrous alcohol and 
ether, and insoluble in weak alcohol, and mineral naphtha. 
Copaivic acid is inodorous, nearly insipid, soluble in 
ether, alcohol, and the volatile oils, and its alcoholic solution 
reddens litmus paper. It forms combinations with bases 
which are generally soluble in ether and alcohol. It has 
the same ultimate composition as colophony, the resin of 
European turpentine, C 40 H 32 O 4 . It is usually amorphous 
like ordinary resin, but Schweitzer has obtained it in color- 
less crystals. Its salt of magnesia is the basis of the of- 
ficinal copaiba pills. 
2d. Let us now examine the proportional relations of 
these constituents as they occur in the copaibas of com- 
merce. 
According to the analysis of Stoltze copaiba contains 
3S. of volatile oil, 52.75 copaivic acid, 1.66 soft resin, 7.59 
water and loss. 
Gerber's analysis of fresh copaiba gives 41. volatile oil, 
51.38 copaivic acid, 2.18 soft resin, 5.44 water and loss. 
Gerber's analysis of old copaiba gives 31.7 volatile 
oil, 53. 68 copaivic acid, 11.15 soft resin, 4.1 water 
and loss. 
Durand found 50 of volatile oil and 50 of resin, including 
a little fatty matter, acetic acid and perhaps water, without 
isolating the copaivic acid. 
