On Gravelly and Calculous Concretions. 299 



Experiment II. 



To the same quantity of" adult urine were added one 

 drachm and halt of acetous acid, which caused a more 

 copious separation and crysiallizadon of this substance 

 with the foregoing appearances. None observable in the 

 standard after twenty- four hours. 



Experiment III, 



To four ounces of urine of a healthy child, who never 

 was observed to pass gravel, and of the usual degree of 

 acidity, was added one drachm of acetous acid, which soon 

 caused au evident and copious separation of crystallized 

 uric acid. The crystals were, however, not quite so co- 

 loured ; the urine of children not being so much impreg- 

 nated with the uree, or colouring matter. No such appear- 

 ance ill the standard after twelve hours or more. 



Experiment IV. 



To four ounces of adult urine, rendered very soon after 

 a tea breakfast, and nearly in a state of urina potiis, was 

 added one drachm of acetous acid. After three hours, a 

 crystallization of minute sandy particles took place. None 

 in the standard, even after three days. 



Experiment V. 



Thirty drops only, of acetous acid, were added to four 

 ounces of the urine of a gouty patient a.'t. sixty, and who 

 sometimes felt some slight gravelly tendency. A very co- 

 pious precipitation of this matter quickly took place. Some 

 observable in the standard, also, the next day. 



Experiment VI. 



To three ounces of healthy adult urine were added a few 

 drops only of citric acid. A distinct crystallization, but 

 extremely minule, took place. No appearance of any in 

 the standard after many hours. The experiment was re- 

 peated with cue drachm of iiltercd citric acid, which onlv 

 hastened the separation and increased the quantity of crys- 

 t.illlne matter. 



Finding, by these experiments, and numberless other?, 

 with a detail of which it would he unnecessary to take up 

 ill'.- iimc of the academy, that tlie acetous and citric acids, 

 blended with ihc urine, ;-cj)arated its uric acid in acrystallizcd 

 fitate, 1 tliOMjrht it might be interesting to investigate what 

 >hc i-flcct of the tartarous acid might be, being that which, 

 in an nncombined and partly conibincu -nit- of :icidule, as 



in 



