. 
{ 38 J 
VIII. Experiments and Objfervations tending to fhow the 
Compofi ition and Properties of Urinary Concretions. By. 
Gzorce Pearson, M.D. F,R.S. Read before the 
Royal Society, December 14, 1797. From the Philofophical 
Tranfactions, 
I, Fifiorical Ob/fervations. 
Tue notion generally entertained, of the nature of urinary * 
eoneretions, confifted with the names given them *, till the 
laft twenty years; although the experiments of Slare, Frsdetis 
Hoffman, and Hales, long before fhowed that thefe fub- 
ftances commonly confift of animal matter. Galen indeed 
imagined that gacye, or vifcid animal matter, is the bafis of 
animal concretions; but, in his days, earth was believed to be 
the bafisof anima! matter. Alkaline medicines were, however, 
employed by the Greek phyficians in difeafes from caleull. 
The experiments of the alchemifts alfo made it appear, 
that earth was only a part of the matter of concretions. It 
was probably the obfervation of the depofition and cryftal- 
lization, of faline bodies, which fuggefted the notion of 
urinary calculi being of the nature of tartar. Such was the 
opinion of Bafil Valentine, and after him of Hochemer, 
better known by the name of Paracelfus; but, whether the 
Jatter adopted the denomination Duwelech from its import, or 
from caprice, has not been explained. Van Helmont, 9 
century after his prototype Paracelfus, being ftruck with the 
experiment in which he difcovered the concretion of falts in 
* Urinary concretions have obtained their denomjnations, like moft other 
things, from their obvious properties. Accordingly, in cnr language, thcy 
are popularly known by the names ftone and gravel, or fand, from their 
refumblance to the ftates of eayth fo named: and we find names of the 
fame import in other languages, fuch as ride, (AKETIEUS;) ASacig, 
(Criivs AURELIANUS;) Japypoc, (ARET£US;) riGidiz, (various au- 
thors); caleulus, (Census and Priny); /abulum, (various authors), 
In other languages, and efpecially in thofe now {poken, it is unneceflary 
so notice names which have the fame meaning. 
diftilled 
