138 CONSTITUENTS OP THE FRUIT OF ANACARDIUM. 
dark oily drops. In the course of twelve hours the liquid 
is clear and nearly colourless ; it is decanted and the residue 
exhausted with alcohol, which leaves a nearly black lead 
compound behind, soluble in ether. The alcoholic extract 
is of a red colour ; it is again mixed with water until the 
appearance of slight opacity, and treated while boiling with 
basic acetate of lead as before, when dark drops of resin 
subside. The clear liquid is united to that previously ob- 
tained, and the residue, if it appear worth while, treated in 
the manner described. To remove the last traces of colour, 
the liquids are boiled for a short time with recently precipi- 
tated carbonate of baryta, when in the course of twelve 
hours a brown stratum is deposited upon the baryta, and 
the solution of the anacardic acid is perfectly colourless. 
Carbonate of baryta does not exert this decolourizing pro- 
perty before the treatment with basic acetate of lead. 
The clear solution of the anacardic acid is now mixed 
with strong alcohol, and while boiling precipitated with a 
neutral alcoholic solution of acetate of lead. The addition 
of alcohol is requisite to facilitate the washing, as other- 
wise, instead of forming a white powder, the precipitate is 
flocculent. This, after washing, is suspended in alcohol, 
and decomposed with sulphuric acid or sulphuretted hy- 
drogen, when, after removing the alcohol by distillation 
and mixing with water, the anacardic acid separates as an 
oily liquid, and as soon as the last traces of alcohol have 
evaporated spontaneously, solidifies to a crystalline mass. 
The acid separated with sulphuretted hydrogen crystallizes 
with greater difficulty, and moreover a peculiar disagreeable 
odour adheres to it, which even accompanies it in some of 
the salts, on which account the separation whh sulphuric 
acid deserves the preference. 
Anacardic acid forms a white crystalline mass, which 
melts at 79° F., and is some time before it returns to the 
crystalline state. It is void of smell, and has a faint aro- 
matic burning taste, but does not blister the skin. It may 
