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ON THE EXAMINATION OF BALSAM OF COPAIBA. 
ed 53.38, and the old sample 64.7S of dry resin, A fluid 
balsam, whose properties I am now studying, only left, 
after having been boiled a sufficient time in water, 40 per 
cent, of a brittle and perfectly dry resin. 
Having been for a length of time, accustomed to a thick 
balsam, we receive less favourably a liquid balsam, which 
is also not so well adapted to the preparation of pills, for 
which purpose it is at present most frequently employed, 
along with wax or calcined magnesia ; and to this we must 
add another circumstance, namely, that the liquid balsam 
usually produces a clouded mixture with pure alcohol, and 
thus, according to the rule laid down in the Pharmacopoeia, 
which usually requires complete solution in this liquid, it 
has been declared impure. 
The complaints of the druggists have been sufficiently 
numerous and well-founded to render it necessary once 
more to examine the action of alcohol on the liquid bal- 
sam. 
Comparative analysis has shown a difference of from 32 
to 54 per cent, in the proportions of the essential oil, and 
looking at it in this light, if the fluidity only depends on 
this circumstance, the liquid balsam may be considered as 
more active than that which is thickened. 
If we except the trial by piolonged ebullition, or by the 
evaporation of the suspected balsam, in which case the 
brittle resin that remains is the only certain proof of the 
absence of a mixture of the fat castor oil, any other isolat- 
ed trial by reaction is seldom sufficient for a preliminary 
proof. So that how good soever the plan of agitating it 
with a solution of caustic alkali may be, the age of the bal- 
sam and the amount of agitation contribute to the more or 
less rapid and complete separation of the transparent soap. 
Small variations, which occur in the case of the thick balsam, 
particularly, may easily be the cause of mistakes as to the 
purity of the balsam. But the action of alcohol is also in- 
sufficient, because it gives no proof of the presence of cas- 
