on the Composition of Urinary Concretions. 35 
were many small white spicula. At about half an inch above 
the carbonaceous residue, dark gray matter had been raised, 
which weighed 15 grains. 
This sublimed gray matter did not contain any ammoniac, 
nor throw down any prussiate of iron, with sulphate of iron. 
It reddened turnsole paper and tincture. It dissolved in caustic 
soda ; from which solution muriatic acid precipitated nothing ; 
for, although on dropping it into the solution milkiness ap- 
peared, the liquid soon grew clear again. 
Ten grains of this sublimate dissolved in four ounces of boil- 
ing water; which being evaporated to half an ounce, there was, 
on cooling, a copious deposit of white spicula .* The sublimate 
had a sharp, but not sour taste. Being boiled in muriatic acid, and 
also in nitric, it did not dissolve at all ; but remained, on evapo- 
ration to dryness, in the same state as before; and it must be par- 
ticularly observed, that it left no red or pink matter, on evapo- 
rating the nitric acid from it. Sulphuric acid did not act upon it 
in the cold; but, when heated, it dissolved it, without efferves- 
cence, from which solution nothing was precipitated by caustic 
soda ; on evaporating it to dryness, black fumes arose, leaving 
behind only a black stain. This sublimed matter did not render 
lime water turbid. Boiled in muriatic acid, so as to carry off all 
but a very little free acid, on the addition of lime water there 
was no turbid appearance, but milkiness ensued on adding 
oxalic acid. 
The spicula , in the 10 grains of sublimate above mentioned, 
seemed to be of the same nature as the matter just described. 
* From the deposition of these spicula by cooling, and from many of the following 
properties, they appear to be analogous to benzoic acid. 
F 2 
•034 z 
'■Ott £ 
