Astringent Substances as Sources of Pyrogallic Acid. 425 
considerable quantities, such as six and eight pounds, I did 
not succeed in the course of several trials in obtaining any 
crystals of gallic acid. I apprehend, therefore, that if oak 
bark contains-any gallic acid at all, it must exist in very mi- 
nute quantity. The tannin of oak bark when precipitated by 
sulphuric acid had a reddish brown colour. When subjected 
to distillation it gave no indication of pyrogallic acid. The 
tannin was also boiled with dilute sulphuric acid. It became 
darker coloured and nearly insoluble either in hot or cold 
water. It was a little more soluble, though very slightly so, 
in alkaline leys. On the addition of an acid a few reddish 
flocks precipitated. Spirits of wine also dissolved a little of 
it, and assumed a light red colour. ‘The tannin of oak bark 
appears, therefore, also to differ from that of nut-galls. 
Divi-divi—The astringent substance by some called Divi- 
divi, by others Libi-divi, has of late years been imported into 
Great Britain from Carthagena in considerable quantity. It 
is the pod of a leguminous shrub which grows to the height 
of between twenty and thirty feet. Professor Balfour informs 
me that its botanical name is Ce@salpin coriaria. It is a 
native of South America, and is noticed by Dr. McFadyen 
in his Flora of Jamaica, as occurring in that island. The 
pods of this shrub, which form the divi-divi of commerce, are 
of a dark brown colour, nearly three inches long and about 
half an inch broad. They are very much curled up, as if 
they had been strongly dried; and contain a few flattish seeds. 
The taste of divi-divi is highly astringent and bitter. The 
astringent matter is contained only in the outer rind of the 
pod; the inner skin, which incloses the seeds, is nearly taste- 
less. The pods are often perforated with small holes, evi- 
- dently the work of some insect. ‘The aqueous solution of 
divi-divi gives a copious precipitate with gelatine, and strikes 
a deep blue with persalts of iron. 
When dried extract of divi-divi was distilled, the liquid 
which passed into the receiver, though it gave no crystals of 
pyrogallic acid, evidently contained that substance, as it ex- 
hibited all its characteristic reactions. 
When divi-divi was treated for gallic acid in the way I 
have already described, I easily succeeded in obtaining a con- 
siderable quantity of reddish-coloured crystals, which, when 
purified like the others with animal charcoal, became per- 
fectly white. ‘They had the usual reactions of gallic acid, 
and yielded pyrogallic acid when distilled. 
When dried at 212° F. and subjected to analysis,— 
I. 0°3034 gramme acid gave 0°550 carbonic acid, and 
0'1018 water. 
