of Urinary Concretions. 53 
animal oxide were exploded; but I am indebted to that 
purfuit for the curious difcovery of the change of the moft 
common bafis of urinary concretions, (the animal oxide,) 
into ammoniac and.carbonic acid, by the oxygen of the 
above acids; which will be found extremely important, as 
it enables us to interpret many phenomena, in a variety of 
cafes befide the prefent. It now appears, that the inflam- 
mation mentioned in one of the above experiments, (and 
which alfo happened in feveral others,) on evaporation of the 
nitric folution of the animal oxide, was from the nitrate of 
ammoniac, the nitrum flammans of the old chemifts, com- 
pounded in thofe experiments. This inflammation takes 
place fometimes, on evaporation of nitric folutions, both of 
urinary concretions, and of urine itfelf evaporated to the ftate 
of foft extra&t, on account of the ammoniac already exifting 
in thefe fubftances. The compofition of ammoniac alfo ex- 
plains the difappearance of the whole matter of fome forts of 
urinary concretions, a very {mall refidue of black matter ex- 
cepted, by repeated affufion and evaporation of nitric acid, 
from the folution of them in this menftruum. 
It remains for me to give an account of the 96 grains of 
powdery matter left on the paper ftrainer, (a;) which are the 
infoluble portion, in lye of cauftic foda, of 300 grains of 
urinary concretions. 
1. A fmall] portion of the infoluble matter, being expofed 
to flame with the blowpipe, did not turn black, nor yield any 
fmell of animal matter; but it became whiter, and I could 
jut agglutinate the powder into one mafs, although J was 
unable to render it fluid. 
2. The filtrated liquid, from a little of the matter boiled in 
water, became very turbid and white with oxalic acid: with 
lime water it grew barely curdy; and it did not alter the co- 
Jour of turnfole, or of violet juice. 
3. The matter diffolved compietely in muriati¢ acid, and 
alfo in nitric acid, without effervefcence. 
i pal te eae! rit 
