C 15 3 
II. Experiments and Observations , tending to show the Compo- 
sition and Properties of Urinary Concretions. By George 
Pearson, M. D. F. R. S. 
Read December 14, 1797. 
I. Historical Observations. 
Urinary concretions have obtained their denominations, like 
most other things, from their obvious properties. According- 
ly, in our language, they are popularly known by the names 
Stone and Gravel, or Sand, from their resemblance to the states 
of earth so named : and we find names of the same import in 
other languages, such as a tQog, (Aretyeus;) xAtamg, (Gelius 
Aurelianus;) tyuppos, (Aretyeus;) a Met, (various au- 
thors;) Calculus, (Celsus and Pliny;) Sabulum , (various 
authors.) In other languages, and especially in those now 
spoken, it is unnecessary to notice names which have the same 
meaning. 
The notion very generally entertained, of the nature of uri- 
nary concretions, consisted with the terms, till the last twenty 
years; although the experiments of Slare, Frederic Hoff- 
man, and Hales, long before showed that these substances 
commonly consist of animal matter. Galen indeed imagined 
that <pAg yfAot, or viscid animal matter, is the basis of animal 
concretions; but, in his days, earth was believed to be the 
basis of animal matter. Alkaline medicines were, however, 
employed by the Greek physicians, in diseases from calculi. 
