32 On Gravelly and Calculous Comreiions. 



and retaining it in solution. That they should still exert 

 their power in the super-carbonated soda water, is rather 

 singular; and we must suppose that, in the temperature of 

 the human body, this superabundant gas (which, for the 

 greater part, is only retained by compression) would be dis- 

 engaged, and leave the alkali to exert its usual properties; 

 and so, 1 would presume, it happens. 



A half pint of soda water was poilred into a large glass, 

 and exposed to the influence of the atmosphere in a tempe- 

 rature of from 60 to 75 degrees. After two «lays it continued 

 to turn litmus red, and only ceased to do so at the end of 

 three. But in Experiment X. we find it in its full gaseous 

 State, still possessing its alkaline influence on the uric acid ; 

 which I would be disposed to attribute to its very weak union 

 to the carbonic acid in the fully carbonated and super-car- 

 bonated slates, as well as to the very weak degree of acidity 

 of the uric acid itself, rendering the most minute portion of 

 all alkaline matter sufficient to its saturation. However this 

 may be, it is obvious that the extraordinary quantity of gas 

 with which these waters are surcharged, is undoubtedly su- 

 perfluous, and may probably prove dangerous. In gouty 

 habits (so subject to these complaints) there is always danger 

 of their inducing spasmodic affections of the stomach. This 

 hasfrequentiv occurred ; and if, to prevent it, we are obliged 

 to add spirituous tinctures, and brandy, why not as well omit 

 this super-saturation at once, and content ourselves with 

 that pleasing degree of it which exceeds but little that of 

 saturation ? 



Nor have the predisposed to apoplexy less to apprehend. 

 And in these cases we find our own physicians, as well as 

 those of the sister kingdom, preferring carbonated potash, 

 or desiccated soda. But, recollecting that I am acting, on 

 this occasion, the part only of the experimenter, T shall now 

 proceed to consider what the action of these saline substances 

 may be on the uric acid, in its concrete or calculous state, as 

 well as on a few others of these concretions, ^hich, though 

 of a different nat are, are of frequent occurrence, and easy 

 solubility. The nature of those employed iu the following 



experiments 



