Q6 On Gravelly and Calculous Concretions. 



kind by our modern chemistry ; and to Beddoes's desiccated 

 soda pills, my colleagues must join with nie in acknow- 

 ledging our greatest obligations. But how account for these 

 good effects ? or what can their modus operandi be? Hie 

 laioTy hoc opus. Carbonates, \vc have always been given 

 to understand, exerted no solvent power on gravelly or 

 calculous matter; and this continues to be the opinion of 

 philosophers, as well as medkal chemists, to this day. We 

 find Fourcroy, in his late elaborate work on this subject, 

 still continuing to assert, (in mentioning the action of va- 

 rious matters upon uric acid,) *' les carbonates alkalines 

 n'ont aucune action sur lui." Nor does the difficulty di- 

 minish with respect to the pure alkalies; for, in the sto- 

 mach and primcB vice, they must return again, to either a 

 carbonated or saponaceous state. My ingenious friend, 

 and master in chemistry, Mr. William Higgins, (in the 

 work already quoted,) emphatically exclaims, *' Why not 

 at once give soap ? why not turn our attention to the mild 

 mineral alkali ?" With regard to the common alkaline car- 

 bonates in use, it m^y be observed that the saturation is 

 not complete; and that the uncombined portion of alkaline 

 matter may still exert its specific powers observable by its 

 detergent quality, as has been so long since well explained 

 by Mr. Kirwan. This explanation, however, could not ex- 

 tend to the potassa carbonata, or crystallized vegetable al- 

 kali, lately introduced, and with equal success. May I be 

 permitted (notwithstanding its use as a test, and non-deli- 

 quescence,) to entertain some doubt of its complete satura- 

 tion ? for that, prepared with the most scrupulous care, still 

 retains its alkaline taste, and acts with energy on the vege- 

 table blues. The carbonic may probably be too weak an 

 acid to entirely annul its alkaline property in any propor- 

 tion that we can possibly unite them in the solid state. 1 

 am informed by Mr. Kirwan, however, that this can be ef- 

 fected ; but the saturation is temporary, and continues only 

 during its most recent state. This we now accomplish, by 

 mechanical means in the fluid one .of our soda and other 

 mineral waters ; where, indeed, the alkali may be consi- 

 dered as in the supcr-carbonatcd state. Now, the success 



attendant 



