; 50 On the Compofition and Properties 
I do not avail myfelf of various other conclufions in this 
place, becaufe they relate efpecially to the agency of medi- 
cines for preventing and removing concretions; and of 
courfe do not properly fall within the views of the Royal 
Society. 
Having found the above precipitate to be an oxide, ‘and 
not, as is commonly fuppofed, an acid, I thought it probable 
that, like other analogous oxides, it was acidifiable, and I 
fufpected that'I had really rendered it into the acid ftate, by 
the nitric acid; which, in the above experiments, (e, 14.) 
had imparted oxygen to it, and thereby rendered it foluble, 
deliquefcent, pungent, and volatile. This change alfo would 
account for the nitric folution not affording the precipitate. 
In order to obtain, for examination, an adequate quantity 
of this fuppofed acid, the following experiments were in- 
ftituted, with the three acids (viz. the oxymuriatic, the 
nitro-muriatic, and the nitric), which can acidify oxides 
analogous to the prefent one. 
Experiment 1, Twenty-five grains of the above animal 
oxide, (for fo I will now venture to call it,) and three ounces 
of nitric acid, of the fpecific gravity of 1,25, were put into a 
retort, and the hydro-pneumatic apparatus was adjoined. 
At a very low temperature, a clear folution was made. 
Firft, foon after the folution began to boil, 23 ounces, by 
meafure, of colourlefs gaz came over, which were fucceeded 
(fecondly), by white fumes, filling the apparatus, and 23 
ouhces more of gaz. Thirdly, a white fublimate afcended, 
and there was a {trong {mell of pruffic acid. The fublimate 
was very readily wafhed out, being very foluble, and tafted 
pungent or fharp, but not four. Fourthly, the diftillation 
being renewed, more white fublimate appeared, but only 3 
different Kinds, as is the cafe with the matter of the brain, liver, voluntary 
mufcles; mucus, &c. Mr, Hunter has difcovereda diftinguifhing fpecific 
property of pus, and one is here indicated for the oxide of urinary con-— 
cretions. 
ounces. 
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