206 On. Gravelly and Calculous Concretions. 



passed iainiediately with the urine, or spontaneously de-=' 

 posited, or precipitated from it ; a circumstance that, for a 

 long time, continued to oive me much surprise, consider- 

 ing the variety of calcuU ; but of the truth of which I was 

 convinced by the examination of many hundred speci- 

 mens, for many years back. 



I was therefore pleased to find, that Fourcroy, for the first 

 time, in his Connoissances Chiniiqucs , asserts, " les sables 

 des reins sont presque toujours de I'acide urique." And in 

 another place he says, speaking of the uric acid, " c'est lui 

 qui forme les sables, qui se crystallize, et s'attacbe aux par- 

 rois de vaisseaux." 



No wonder, then, that calculi of this kind should be of 

 most frequent occurrence ; and that, of five hundred ana- 

 lysed by Fourcroy, one-fourth should entirely consist of it, 

 besides its occasional admixture with the remainder; and 

 of three hundred, examined by Pearson, the greater number 

 ■were found to be of this nature. 



Having premised these necessary observations, we have 

 now to consider to what circumstances we mav attribute its 

 separation, in a crystallized or aggregate state, from its na- 

 tural solvent ; the only condition in which it can be pro- 

 ductive of inconvenience, or diseases of this kind. And 

 first, I would observe that, being a natural secretion, of 

 which the urine is only the veliicle destined to carry it out 

 of the system, it must be subject to the same derange- 

 ments with the other secretions of the human body, and 

 may, of course, sometimes exceed in quantity, and at other 

 times be more deficient; which last circumstance seems to 

 take place during the continuance of acute diseases. 



Tliat a morbidly increased secretion does frequently oc- 

 cur, and that, too, independent of external causes, we have 

 the ujost satisfactory proof of in the hereditary dispositions 

 of many faniilies to this complaint: And, indeed, when we 

 consider the same to take place, relative to the functions 

 and secretions of the liver, we must not be surprised at si- 

 milar deviations in those of the kidneys. Here, truly, 

 thev are of more mischievous tendency, as, from the very 

 sparing solubility of the uric acid, (even in its own natural 

 menstruum,) the smallest excess in quantity must subject 

 it to precipilaiion. 



Having premised these necessary considerations, I shall 



proceed to inquire into those circumstances which the ex- 



pi rience and observation of all times have pointed out to 



U3 as the most fri.quent occasional causes of these maladies, 



5 ami 



