306 On Gravelly and Calculous Concretions. 



Eighteen ounces of urine were divided into three equa-I 

 parts. To the first were added five drops of sulphuric acid ; 

 to the second, tea; and to the third, fifteen. In the first 

 the magnifier very soon discovered minute floating niole- 

 culsc, gradually assuming the crystalline form, &:c. as so 

 often before described. In the second, the same appear- 

 ances, but more immediately and copiously produced. But 

 in the third, so considerable as to excite my astonishment. 

 For here, besides the same extremely minute crystals which 

 adhered to the entire sides of the phial, the bottou) appeared 

 covered with a mixture of crystalline and red pulverulent 

 matter ; the latter in great proportion, and probably pre- 

 vented from crystallization by its hasty deposition. Here, 

 then, that increased proportion of calcareous phosphate and 

 animal gelatinous matters, (which always takesj place in 

 gout, and could not be expected here,) would seem only 

 wanting to form a sort of synthetic approximation to the^ 

 gouty sediment. 



The unusual proportion of deposited uric acid in this 

 experiment created some suspicion that the phosphoric acid 

 might, by a combination with some of the principles of 

 this very compound fluid, give rise to some artificial forma- 

 tion of it on this occasion. 



To the filtered liquor, therefore, of No. 3, were again 

 superadded five drops, which in twenty-four hours caused 

 'a further separation of a very few crystals only. It was 

 filtered a third time, and eight drops more added ; but 

 without the smallest appearance of a single crystal after 

 four days. The additional acid, then, only more cfi'ectualljr 

 and speedily determined the separation of the quantity na- 

 turally contained in urine ; its more divided pulverulent ap- 

 pearance adding considerably to its volume. 



It now only remained to demonstrate the identity of these 

 various precipitates with the naturally deposited matter of 

 gravel. For, though it could not be well mistaken for any 

 other saline composition in urine ; yet, as external charac- 

 ters are, even in the hands of a Rome de Lisle, or an abbe 

 Haiiy, fallacious, the following, and concluding one, on 

 the subject of acids was instituted. 



Experhneiit XV, 



To two drachms of this artificial gravelly matter was gra- 

 dually added one ounce of nitrous acid, which acted on it 

 with eftervescence, and dissolved the whole, with the ex- 

 ception of some small, floating, succulent, animal particles, 

 so well described by Bergman. 



The 



