On Gravelhj and Calculous Concretions. 33 



experiments was always previously ascertained and specified ; 

 they were also carefully weighed and dried, both before and 

 after immersion in their several menstrua. 



Dr. Percival, of Manchester, as well as others, having 

 experienced the solvent power of the plain mephitic, or car- 

 bonated water, on urinary calculi, it was thought proper to 

 repeat his experiments. 



Experiment T. 

 A fragment of a calculus, weitjhing twentv-three grains, 

 and of the uric acid kind, was suspended by a thread, ior 

 forty-eight hours, in Nooth's apparatus, already nearly filled 

 with highly impregnated aerated water, and still exposed to 

 a stream of carbonic acid gas : temperature 58 degrees. 

 When taken out, and dried, weighed, as before, twenty- 

 three grains. 



Experiment II. 



A fragment of a calculus, of the same kind, weighing 

 forty grains and three quarters, was suspended, as before, in 

 Nooth's apparatus, for forty-eight hours : temperature vary- 

 ing from forty to fifty-five degrees. On being taken out, 

 and dried, was found to have sustained no loss. 



Experiment III. 



An entire calculus, of a rough and sandy appearance, 

 chiefly of the uric acid kind, but with some extremely mi- 

 nute intermixed particles of the ammoniacal magnesian phos- 

 phate, weighing fifty-two grains, was suspended, as before, 

 for forty-eight hours, in Nooth's apparatu-. After being 

 taken out, and dried, was found to weigh fifty-one grains 

 and a quarter ; so that there was here a loss of three cpiar- 

 ters of a grain ; undoubtedly of the ammouiacal magnesian 

 phosphate. 



Experiment IV. 



Wishing to see whether even increased temperature would 

 add to ihe solvent power of carboTiic acid, a fragment of 

 calculus, of the uric acid kind, weighing twentv-two grains, 

 was immersed, as before, for forty-eight hours, in three 

 fiunces and a half of highly impregnated carbonated water. 



Vol. 21. No. 93. Feb. 180<J. C ia 



