% 
^84 Selections. [no. 4, new series, 
copaiba of commerce. This hard resin (copaivic acid) being most pro- 
bably the active principle of balsam of copaiba, I am induced to think its 
quantity and purity in the one I have examined is indicative of its supe- 
rior value as a medicament. The dark colour of the balsam may perhaps 
limit its employment, but the large quantity of copaivic acid it contains 
renders it valuable, as the latter may be made available by heating the 
filtered balsam to the boiling point with a smaH quantity of caustic potash 
or soda lye, of sp. gr. 1.34, and separating the resinate of potash or soda 
from the essential oil. The alkaline resinate may then be dissolved in 
water, giving a colourless solution (simil'ir to Frank's specific), or the 
balsam may be treated with magnesia to form the ordinary copaiba pill. 
I have in conclusion remarked : — * 
1st, That the essential oil obtained by the distillation of balsam of co- 
paiba has, like several other hydrocarbons, the property of dissolving 
indigo. 
2ndly, The new variety of balsam above described presents the curious 
property of becoming gelatinous (so much so that the tube may safely be 
inverted), if heated to 230*^ Fah., even if a sealed tube be employed. 
This character being dissimilar to the one given in the same circumst-ances 
with such other balsams as I had at my disposal, I am induced to attribute 
it to the large amount of hard resin" it contains. 
Srdly, Balsams of copaiba in general give, on distillation with two per 
cent, sulphuric acid, a beautiful blue volatile oil. Chlorine^ hypochlorite 
of lime, and bichromate of potash, give a similar character with the bal- 
sam, which appears to me to be due to the oxidation of the hard resin, 
as I have been unable to obtain but a small proportion of the blue-colour- 
ed oil when I employed a balsam containing " soft resin," comparatively 
to when I made use of the one above described, which, as I have already 
remarked, contains only " hard resin." A further support of this view 
is, that pure essence of copaiba assumes no blue colouration when distilled 
as above. 
4thly, That cold sulphuric acid produces a purple colouration with bal- 
sam of copaiba, similar to that obtained by its action on cod-liver oil. 
Such being the case, it is probable that a small quantity of it, mixed with 
olive or soVne other oil, may be sold by unprincipled persons as genuine 
cod-liver oil. — Pharmaceutical Journal, XIV. G5. 
In 1856 the same substance was again noticed by Mr. Daniel 
Hanbtjey under its ordinary name of Wood Oilj a suhstitute for 
Cojiaiha. 
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