on the Compositions of Urinary Concretions. 41 
soda lye, discharged very little ammoniac. On distilling this 
mixture to one ounce, a very small proportion only of ammo- 
niac was found in the distilled liquid. The residuary ounce of 
alkaline liquid was filtrated, and mixed with the water of elu- 
triation of the undissolved matter. One half of those liquids, 
on evaporation to dryness, afforded a dark brown matter, 
amounting to 20 grains, which consisted of phosphate of lime 
and animal matter. To the other half of the alkaline liquids 
was gradually added muriatic acid, which occasioned a deposit, 
in small proportion, of matter that dissolved in nitric acid, 
but which, on evaporation to dryness, left behind only a 
brownish matter, consisting of phosphate of lime and animal 
matter. 
7. The residuary insoluble substance in caustic lye, (b.) 
under the blowpipe, first turned black, and then grew white, 
but could not be melted. 
By diluted sulphuric acid it was decompounded. On the ad- 
dition of nitrate of mercury, to the filtrated liquid, it yielded 
phosphate of mercury; and, with oxalic acid, it afforded oxalate 
of lime ; but no sulphate of magnesia was found remaining after 
these precipitations were produced. 
These experiments fully demonstrate, that the above con- 
cretion of a dog contained none of the uric or lithic oxide 
above described, but that it consisted, principally at least, of 
phosphate of lime, phosphate of ammoniac, and animal matter. 
The present instance leads me to explain the reason of the 
fusibility of calculi. This is demonstrated, by the above expe- 
riments, to depend upon the discharge and decomposition of 
the ammoniac of the phosphate of ammoniac, during the burn- 
ing away of the animal matter; hence the residuary phosphoric 
MDCCXCVIII, Q 
-0A& S' 
* 
