Dr. Pearfon’s Laperimentson Calcul. - 38% 
which by expofure tothe air foon depofits both carbonat of 
lime and ‘the lithic acid feparate from each other, proves 
that the atmofpheric ‘carbonic acid decompofes the cal- 
‘eareous lithidt ‘which was there formed. 8. Its almoft 
otal folubility (except <4.) in a ley‘of cauftic potafh, which 
often difengages much ammonia. 9. ‘Its precipitation of a 
golden yellow colour ‘from this alkaline folution by the 
‘acetous acid, which feparates from it the lithic acid in fmall 
white brilliant and almoft pulverulent needles, and which 
furnifhes more than a half of the cryftallifed lithiat of potafh. 
10. This precipitation of ‘the lithic acid from the alkaline 
folution by the acétous acid, given as a good procefs for 
procuring this animal acid pure. 11. The folubility of the 
calculus fometimes entire, fometimes in powder, in the 
oxygenated muriatic acid, which at firft afforded me the 
hope of a lithontriptic ; but which being deftroyed by other 
fueceffive experiments prefented only a fingular fact worthy 
of being further inveftigated. 12. The action of the fire 
and diftillation in a retort upon the calculus of the human 
bladder, ufing a quantity five times greater than that em- 
‘ployed by Dr. Pearfon, and which gave me‘as produéts near 
“a quarter of a fublimated lamellated aeid, ftill analogous to 
the lithic acid; fome drops only of water’ and thick oi, 
“fixed, containing a little pruffiat of ammonia; 7 concrete 
“‘earbonat of ammonia, a bulk of more than fix kilogrammes 
“of water in gas, 3 of which were carbonic acid; a ‘coal 
‘weighing a little more than a quarter of the calculus, ‘and 
*which yielded only 5 of its weight of afhes, without: ~ 
fenfible trace of lime. 
All thefe fa&ts, which I was obliged to concentrate herein 
fome manner in. order to render them’ more firtking, ferved 
to confirm the firft refults of Scheele and Bergmann ;) and 
enabled me to add ‘feveral obfervations ‘which had efcaped 
*them. I had concluded with them that the human:urinary 
ealeulus, whether that of the reins or that of the bladder, 
——e—ee 4 matter different from all. other animal, fub- 
ftance, 
