on Guaiacum. 
97 
subjected to the action of bodies, which readily communicate 
oxygen, such as nitric and oxy-muriatic acids ; and the rapi- 
dity with which it dissolves in the former. 
3. By being converted into a more perfect resin ; in which 
respect guaiacum bears some resemblance to the green resin 
which constitutes the colouring matter of the leaves of 
trees, &c.* 
4,. By yielding oxalic acid. 
5. By the quantity of charcoal and lime which are obtained 
from it when subjected to destructive distillation. 
§ V. 
From the whole therefore of the above mentioned pro- 
perties, it evidently appears that guaiacum is a substance very 
different from those which are denominated resins, and that 
it is also different from all those which are enumerated 
amongst the balsams, gum resins, gums, and extracts : most 
probably it is a substance distinct in its nature from any of 
the above, in consequence of certain peculiarities in the pro- 
portions and chemical combination of its constituent ele- 
mentary principles ; but as this opinion may be thought not 
sufficiently supported by the facts which have been adduced, 
we may for the present be allowed to regard guaiacum as 
composed of a resin modified by the vegetable extractive 
* This substance was found by Proust to be insoluble in water, and soluble in 
alcohol. When treated with oxy-muriatic acid, it assumed the colour of a withered 
leaf, acquiring the resinous properties in greater perfection. Vide Thomson’s 
Syst. of Chemistry, 2d edit. Vol. IV. p. 318. 
MDCCCVI, O 
