Dr , Wollaston’s Analysis, &c. 387 
on any direct experiments, nor is it (to my knowledge) more 
ably supported than by Mr. Forbes, who defends it solely by 
pathological arguments from the history of the disease. Had 
he undertaken an examination of the substance itself, he would 
have found that, instead of a mere concrete acid, the gouty mat- 
ter is a neutral compound, consisting of lithic acid and mine- 
ral alkali ; as the following experiments will prove. 
(1.) If a small quantity of diluted vitriolic acid be poured 
upon the chalk-stone, part of the alkali is extracted, and crys- 
tals of Glauber’s salt may be obtained from the solution. Com- 
mon salt may still more easily be procured by marine acid. The 
addition of more acid will extract the whole of the alkali, leav- 
ing a large proportion of the chalk-stone undissolved ; which 
exhibits the following characteristic properties of lithic matter. 
(a.) By distillation it yields a little volatile alkali, Prussic 
acid, and an acid sublimate, having the same crystalline form 
as the sublimate observed by Scheele. 
(6.) Dissolved in a small quantity of diluted nitrous acid it 
tinges the skin with a rose colour, and when evaporated leaves 
a rose-coloured deliquescent residuum. 
(c. ) It dissolves readily in caustic vegetable alkali, and may 
be precipitated from it by any acid, and also by mild volatile 
alkali ; first as a jelly, and then breaking down into a white 
powder. 
(2.) In distillation of the chalk-stone the lithic acid is de- 
composed, and yields the usual products of animal substances, 
viz. a fetid alkaline liquor, volatile alkali, and a heavy fetid 
oil, leaving a spongy coal; which when burnt in open air 
fuses into a white salt, that does not deliquesce, but dissolves 
MDCCXCVII. 3 E 
