On the Animal Calculus. 2 1 1 
! advifeable to attempt the Ufe of it in a hu- 
man Bladder ; neither do I here give an Ac- 
count of it with any fuch View ; my Defign 
herein being only to fliew, that this is at leaft 
fome Advance towards difcovering a (afe diP- 
folvent for moft Gravels and fome of the fof- 
tcr kinds of Calculi-, but as to the harder 
kinds, on which nothing has hitherto been 
found to have any effe£t towards a Diflblutionj, 
except Aqua-fortis^ there is little Hopes of ever 
finding a fafe Diflblvent for them. But as to 
the fofter kinds there are fcveral mild acid Mix- 
tures that will diflblve them, when laid to foak 
in them for a few Days. 
4. I tried to make this Liquor more mild by 
mucilaginous Mixtures ; fuch as Solution of 
Gum Arabick, and Decodion of Comfrey 
Root ; but I did not find it fignify*d any thing ; 
it ferved only to increafe the Froth’ in the Ef- 
fervefcence, which was alfb the Inconvenience 
of ufing Urine inftead of Water : For I diP* 
folved feveral Pieces of Calculus^ with Urine 
Solution of Sal Tartar and Oil of Sulph. fo 
that a little Urine in the Bladder would be no 
Irnpediment to the Operation of this Liquor. 
P E X P B « 
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