on Guaiacum, 
9i 
2. Alcohol dissolves guaiacum with facility, leaving some 
extraneous matter, which generally amounts to about 5 per 
cent. 
This solution is of a deep brown colour; the addition of 
water separates the resin, forming a milky fluid which passes 
the filter. 
Acids produce the following changes : 
A. Muriatic acid throws down an ash-coloured precipitate, 
which is not re-dissolved by heating the mixture. In this 
case the resin appears but little altered. 
B. Liquid oxy-muriatic acid when poured into this solution, 
forms a precipitate of a very beautiful pale-blue colour, which 
may be preserved unaltered. 
C. Sulphuric acid, when not added in too large a quantity, 
separates the resin of a pale green colour. 
D. Acetic acid does not form any precipitate. This acid 
is indeed capable of dissolving most of the resins. 
E. Nitric acid diluted with one-fourth of its weight of 
water, causes no precipitate till after the period of some hours. 
The liquid at first assumes a green colour, and if water be 
added at this period, a green precipitate may be obtained ; 
the green colour soon changes to blue, ( when by the same 
means a blue precipitate may be obtained ; ) it then becomes 
brown, and a brown precipitate spontaneously makes its ap- 
pearance, the properties of which will be afterwards men- 
tioned. 
The changes of colour produced by nitric, and oxy-muriatic 
acids, in the alcoholic solution, are very remarkable, and I 
believe peculiar to guaiacum : there is moreover much reason 
to suppose that the above alterations in colour are occasioned 
N 2 
