» of Urinary Concretions. 139 
indeed, fometimes, on the affertions of perfons who colle& 
fpecimens. 
1. This concretion, which Dr. Baillie was fo good as to 
give me, was of a blackith colour, was very brittle and hard, 
and had no fmell or tafte. It felt heavier than human 
urinary calculi. 
2: Under the blowpipe it became quite black, and emitted 
the fmell, weakly, of common animal matter. It was re~ 
duced very little in quantity, and fhowed no appearances of 
fufibility, after being expofed for a confiderable: time to the 
moft intenfe fire of the blowpipe. 
3. Muriatic acid diffolved this concretion, with effer- 
yvefcence, yielding a clear folution; which, on evaporation to 
drynefs, left a black and bitter refidue. 
4. A little of the refidue (3.) being boiled in pure water, 
to the filtrated liquor fuperoxalate of potafh was added; 
which occafioned a very turbid appearance, and copious 
white precipitation. 
_ 5+ Nitric acid alfo readily diffolved this concretion, with 
effervefcence. The folution being evaporated, partly to dry- 
nefs, and partly to the confiftence of an extract, the dry 
refiduary matter was white and bitterifh, and the extract- 
like part fhowed no figns of fufibility under the intenfeft fire 
of the blowpipe. 
6. A little of the concretion, being triturated with Hie of 
¢auftic foda, emitted no fmell of ammoniac. 
From thefe experiments it appears, that this calculus, like 
the former one from a rabbit, confifts of carbonate of lime 
and commen animal matter. 
A renal calculus of a horfe, in Mr. Heavifide’s collection, 
appeared, on examination, to confit of carbonate of lime and 
common animal maiter. 
Another {pecimen, however, of renal calculus of a horfe, in 
the fame collection, marked No. 3. was found to confift of 
phofphate of lime, phofphate of ammoniac, and common 
animal matter, It was fufed under the blowpipe, ; 
The 
