GUAIAGUM OFFICINALE. 
141 
guaiacurn tree also yields a spontaneous exudation from the bark, 
which is called the native gum ; this is brought to us in small irregular 
pieces, of a bright semi-pellucid appearance, and differs from the 
former, in being much purer. 
Chemical Properties. Guaiacum is of a friable texture, 
of a dark greenish colour,* and sometimes of a reddish hue : it has 
a pungent acrid taste, but little or no smell unless heated ; it contains 
more resin than the watery extract of the wood, and more gummy 
matter than the spirituous extract. Alcohol forms, with guaiacum, a 
deep brown-coloured solution ; which is rendered milky by the addition 
of water, and precipitated pale green, by the muriatic and sulphuric 
acids, and brown by the nitric.f Guaiacum is soluble in fifteen parts 
of solution of potass, and in thirty-eight of ammonia ; it differs from 
the resins, in the change of colour produced on it by air and light, 
in the action of the acids, and in not forming tannin when heated with 
nitric acid ; it gives a blue colour to vegetable matters containing 
gluten, and to the mucilage of gum arable and milk. 
Medical Properties and Uses. The wood, gum, bark, fruit, 
and even the flowers of this tree, have been found to possess medicinal 
qualities, but it is only the wood and resin which are now in general 
use in Europe ; the efficacy of the former, depending entirely on the 
quantity of resinous matter it contains. The bark containing less 
resinous matter than the wood, and is not so powerful a medicine, 
though in a recent state strongly cathartic ; the fruit is purgative, and 
for medicinal use, far exceeds the bark ; a decoction has been knowu 
to cure the venereal disease, and even the yaws in their advanced stage, 
without the use of mercury j the flowers are laxative, and im 
Jamaica, are commonly given to children in the form of syrup, which 
in appearance much resembles that of violets. J 
Guaiacum was first introduced into Europe as a remedy for the 
venereal disease, and was used in Spain so early as 1508 ; the great 
♦ According to Dr. WoUaston, this green colour is produced by the action of air and 
light, which is effected by the most refrangible rays ; and in the refrangible rays it is 
disoxidized, and the yellow coloar returns. 
+ Sulphuric acid dissolves gum guaiacum ; the solution is a fine claret colour, and on 
adding water lets fall a lilac precipitate. Nitric acid dissolves it : ranch nitric vapour is 
emitted, and on distillation oxalic acid is formed ; dilute nitric acid only changes it into 
a brown resin. Spirit of salt dissolves a small portion; this solution is brown: by 
distillation it yielded 5.5 per cent, of acidulous water ; 24.5 of thick brown oil ; 30 of 
a fine oil; 30,5 of charcoal, and 9.5 of gas ; chiefly carbonic acid gas, and carbnretted 
hydrogen. Gray's Elements, p. 271. 
X Long's History of Jamaica, — Des Marohais Voyage en Guineeet Cayenne. 
