2:5 V 



"■ a more powerful and active solvent, than any hitherto 

 " known, shall be discovered; it is highly probable, that 

 " such a discovery can only be made, by a rational and 

 " chemical inquiry, into the powers af difterent bodies of 

 " combining witli the contents of the urine, and preserving 

 " them in a fluid state out of the body." Now, on the other 

 hand, we may presume, that,- whatever substances cause a 

 separation, or precipitation of uric acid, in an aggregate 

 state, from healthy urine, will give rise to these disorders; 

 Por, we are not to forget, that the uric acid, which forms 

 so large a proportion of caculous concretions, and the en- 

 tire of the gravelly, is a natural secretion from the bloody 

 performed by the functions of the kidneys, and excreted by 

 the urine; and can only be prejudicial, by a previous 

 morbid separation from itj within the body* With this- 

 necessary view of the subject before us, (for which we are, 

 as already observed, indebted to Boerhaave,) I resolved 

 to try, First, what might be the effects of acids of diffe- 

 rent kinds, on healthy urine, as to their influence, in caus- 

 ing this same previous precipitation; and, Secondly, that 

 of alkaline substances, in preventing it. And, here, it must 

 be observed, that, to draw any satisfactory conclusions, 

 from experiments, made Avith these substances out of the 

 body; we must suppose they reach the kidneys, and blend 

 with the urine, still possessing their relative distinctive pro- 

 perties: and, that this takes place, we have every reason 

 to presume. Doctors Percival and' Saunders, Mr. Bewley, 

 and others, have ascertained the presence of carbonic acid, 



in 



