139° On the Compofition and Propertics * 
The fublimate of carbonate of ammoniac amounted to 2@ 
grains; and it was black empyreumatic animal oil which, 
ftained the tube. , 
This experiment was repeated, on 120 grains of a nut- 
_ brown, very light, urinary concretion. The refult was not 
very different from that of the former experiment, except 
that the gaz contained a portion of hydrogen gaz. There 
were Zo grains of the above defcribed /picula, principally 
mixed with carbonaceous matter: they were light, and had 
only a very flight fherp and bitter tafte. 
The experiment repeated a third time, with 80 grains of 
urinary concretion, afforded 15 grains of the white Spicule. 
above defcribed, mixed with carbonaceous matter. Thefe I 
found did diffolve in a large proportion of muriatic acid ; 
which folution yiclded them, on evaporation, in the fame 
ftate as before. Under the flame applied by the blowpipe, 
they firft melted, and then evaporated, without any {mell; 
Jeaving a flight black mark. Turnfole was reddened by thefe 
Sprcula. 
In a fourth experiment, I found the white /picula con- 
tained in the carbonaceous matter united, on boiling, with 
carbonate of foda, as, well as with cauftic foda; but, as be- 
fore, muriatic acid precipitated nothing from the folution. 
Thefe; yfpicula could not be diffolved in nitric acid 5 nor did 
the folution of them in water become turbid with oxalic 
acid. Their tafte was, as before, rather bitter and fharp 
than four. A very fuffocating fmell iffued forth, on break-. 
ing the tube ufed in this experiment, but it was.not from 
fulphur, nor from pruffic acid. 
Thefe experiments afford evidence of the wide difference 
between the animal oxide aboye defcribed and the acid 
fublimate of Scheele*. 
“From thefe experiments, it now appears very doubtful whether the 4- 
thie acid of Scheele exifis as a conftitucnt of urinary concretions, or is com~ 
pounded, in confequence of a new arrangement taking place, of the ele-. . 
mentary matters of the concretion, by the agency of fire; but it is demon. 
firated, that the urinary animal oxide is really a conftituent part, and even 
a principal one, of almoft all human urinary calculi. If 
