on the Composition of Urinary Concretions. 2 $ 
3 - Lye of mild potash, or subcarbonate of potash, being 
dropped into the solution ( e , 2.) with its crystallized deposit, 
the crystals at first seemed to dissolve; but, on standing, a 
great part of the matter was deposited, and the liquid remained 
turbid. 
4. The precipitate being boiled with lye of carbonate of 
soda, more seemed to be dissolved than in pure water; but 
the solution was not clear, and,, on evaporating it nearly to 
dryness, and pouring cold water upon it, on a paper strainer, 
scarcely any thing but the soda passed through with the water ; 
the precipitate remaining behind on the paper. The result 
was the same, when this experiment was made with a lye of 
carbonate of ammoniac. The result was also the same, with 
water in which red oxide of mercury had been boiled ; which 
was also boiled with this precipitate, and filtrated after cooling. 
5. A little of the precipitate being triturated with quick- 
lime, hot water was poured upon it. The filtrated liquor gave 
the precipitate back again, on adding muriatic acid. 
6. The precipitate exposed* to flame, with the blowpipe, 
turned black, emitted the smell of burning animal matter, and 
evaporated or burnt away without any signs of fusion ; stain- 
ing the platina spoon black. 
7. Five grains of the precipitate, in half an ounce of water, 
were left to stand in a warm room, during the months of Au- 
gust and September last, without any signs of putrefaction ap- 
pearing, or any obvious change taking place. 
8. Twenty-four ounces of boiling water were saturated 
with the precipitate, and divided into six portions ; from each 
of which, on cooling, most of it again precipitated. 
The first portion, on boiling with a little lye of carbonate of 
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