68 Brande on (he Medico-Chemical 



specific gravity of urine, and consequently to render the sepa- 

 ration of its solid contents more likely to occur, they should on 

 that account only be avoided ; but when conjoined, as they often 

 are, with sedentary habits, the powers of the digestive organs be- 

 come impaired, there is more or less habitual costiveness, and a 

 corresponding change in the secretion of the kidneys, by which it is 

 rendered more prone to sabulous deposits, always ensues. 

 Hence it is, that writers on the present subject have properly 

 advised plain food, moderate exercise, and abstinence from 

 fermented liquors ; it is also I think right, in most cases, to 

 enjoin the liberal use of aqueous drinks, by which the urine be- 

 comes diluted, and consequently will have less tendency to form 

 any deposit. 



But all experience shows, that whatever deranges the 

 stomach and bowels, and the other organs concerned in diges- 

 tion, more especially the liver, produces corresponding mischief 

 in all these calculous cases ; hence the apparent success of very 

 opposite modes of treatment, and the probability that calculus 

 is in many instances to be considered as a symptomatic disorder; 

 and hence also the beneficial effects of mild aperients, tonics, 

 bitters, ^c, and the great advantage of moderate horse exer- 

 cise, where it is not forbidden by irritation in the kidneys. 

 There can, on the other hand, be little doubt, that violent ex- 

 ercise may, for many reasons, be prejudicial ; and, among 

 others, by occasioning profuse perspiration, which carries off a 

 portion of water by the skin, that would otherwise have passed 

 through the kidneys. 



Of the calculi which we are now considering, those formed of. 

 uric acid are, as I have already observed, by far the most fre- 

 quent ; and it is of this substance that the calculi retained in 

 the kidney, and filling the uifundibula and pelvis, and often in- 

 creasing to such a size as to obliterate a great portion of the 

 glandular structure, are almost exclusively formed ; hence it is 

 always an object to obtain the expulsion of a calculus from the 

 kidney as soon as possible, and to prevent its increase. 



The symptoms of kidney calculus are of very dift'erent shades 

 of violence, and sometimes so trifling, that little is suspected 



