On Gravelly and Calculous Conerelions. 201 



who could have no clear ideas oF the subject ; yet the better 

 illustration of my object, as well as a sense of justice, oblige 

 me to 2;o as far back as Van Helniont, whose great ihougii 

 eccentric genius first observed that the subject matter of 

 calculus existed in the urine itself. But the flighty extra- 

 vagance of his ideas, of which he has given us a specimen 

 on this subject m his Treatise dt Litluasi, (a wonderful 

 pruduction for the time,) caused little attention to be paid 

 to his opinion ; and it was reserved for the capacious and 

 learned genius of Bjcvhaave first to ascertain, hevond future 

 doubt, the presence of gravelly matter as a natural consti- 

 tuent part of urine, kept in chemical solution in it, and eli- 

 minated hv it out of the hvstem. Of this important fact 

 no material use was made, until tlie all-pryina" genius of the 

 immortal LinncBus induced him to request hisfnend Schecle 

 to turn, for a moment, his great chemical abilities to the 

 investigation of this subject : with what success is but ton 

 well known. And from this agaiii had aiisen the further 

 prosecution of this inquirv bv the celebrated Bergman. 



The result of the analysis of the latter was highly ho- 

 nourable to the former chemist, as they perfectly aovced 

 HI almost every particular, with the exception of some 

 .small quantity of insoluble matter, and the presence of 

 lime, observed by Bergman : a difference now very easilv 

 accounted for; the former having examined calculi of the 

 pure lithic acid, or, as it is now termed, uric kind, (by far 

 the most common species,) and entirely soluble in pure al- 

 kaline lixivia and nitric acid ; the latter, those of the mixed 

 kind, consisting also chieflv of iithic acid, but with inter- 

 posed laminae J or probably a nucleus of cither calcareous 

 phosphate or oxalate of lime, which frequcntlv occurs in 

 a very large proportion of these concretions. We may also 

 observe, that Bergman had not, at this period, an adequate 

 idea of the large proportion and insolubility of animal matter 

 contained in them. 



From their joint analysis it was, for the first time, proved 

 «hat the subject matter of gravel, and of a very large pro- 

 portion of calculi, was present in a state of real chemical 

 solution in all healthy urine; that it was possessed of the 

 following distinguishing chemical properties: 



Insipid, inodorous, crystallizable, nearly insoluble in cold 

 water, and only soluble in some thousand times its weight 

 of boiling water ; separable aaain from this, upon cooling, 

 in a beautiful and peculiar crvstalline form ; of easy solu- 

 bility in pure alkaline lixivia, which it renders sweetish, 

 «nd neutralizes; precipitable from these again bv the 



weakest 



