OBSERVATIONS ON COPAIBA. 293 
with one-sixteenth of magnesia and set aside 24 hours 
only partial union followed, a part of the magnesia pre- 
cipitated, and a part was taken up by the oleo-resin, which 
remained turbid. 
(c.) This specimen has a thick consistence,itssp. grav. .983, 
is several years old, but its origin is not known, although it 
looks like that from Angostura. It consists of 50 parts of vola- 
tile oil, and 50 parts of resin. The resin is pulverizable, and 
quite acid to litmus when dissolved in alcohol. Heated with 
one-sixteenth of magnesia, it became tolerably consistent on 
cooling, but did not acquire a pillular consistence after 36 
hours. 
{d.) This sample obtained as Angostura copaiba, has a 
density of .985, is transparent, has a light brown color,correct 
odor, and thick consistence. It consisted of 35 parts of oil and 
65 of resin. The resin was not fragile and pulverizable, but 
soft and sticky between the fingers. Heated with one-six- 
teenth of magnesia, it acquired on cooling, a thick consist- 
ence, and at the expiration of 36 hours its consistence was 
firmer than that of e. The resin was quite acid to litmus. 
(e.) This specimen has been in my possession several years, 
it was obtained as " solidifiable balsam," but its origin is 
unknown. Its color dark yellowish brown, consistence 
thicker, its odor more aromatic than either of the preceding, 
and its density .9S6. It consisted of 34 parts of volatile oil 
and 66 parts of resin, the alcoholic solution of which was 
strongly acid to litmus paper. When heated with one-six- 
teenth of magnesia, its consistence was almost pillular on 
cooling, and after 24 hours was fit for use. 
(/.) This specimen was oil of copaiba obtained by dis- 
tillation, that had been kept five years in a cracked*bottle,so 
as to admit the air. Its consistence is thicker than either of 
the preceding copaibas, has a bright amber color, is per- 
fectly transparent, readily soluble in commercial alcohol, and 
its solution hardly reddens litmus paper. It consists of 
volatile oil 66, soft resin 34. 
23* 
