" Gouty and Urinary Concretions. 389 
cooling the lithic crystals form, as in the preceding experi- 
ment. 
In each case the crystals are too small for accurate exami- 
nation, but I have observed, that by mixing a few drops of 
caustic vegetable alkali to the solution previous to the decom- 
position, they may be rendered somewhat larger. At the first 
precipitation, the crystals from gouty matter were not similar 
to those of lithic acid ; but by redissolving the precipitate in 
water with the addition of a little caustic vegetable alkali, and 
decomposing the solution as before, while hot, the crystals 
obtained were perfectly similar to those of lithic acid pro- 
cured by the same means. 
Such then are the essential ingredients of the gouty concre- 
tion. But there might probably be discovered, by an examina- 
tion of larger masses than I possess, some portion of common 
animal fibre or fluids intermixed; but whatever particles of he- 
terogeneous matter may be detected, they are in far too small 
proportion to invalidate the general result, that ‘ gouty matter 
‘ is lithiated soda/ 
The knowledge of this compound may lead to a further 
trial of the alkalies which have been observed by Dr. Cullen 
to be apparently efficacious in preventing the returns of this 
disease (First Lines, dlviii.) ; and may induce us, when cor- 
recting the acidity to which gouty persons are frequently 
subject, to employ the fixed alkalies, which are either of 
them capable of dissolving gouty matter, in preference to the 
earths (termed absorbent) which can have no such beneficial 
effect. 
3 E 2 
