Ort Grai^lly and Caladous Concretions. 30l- 



Half an ounce only of the common soda water of the 

 shops, prepHred by iMr. Kinsley, was added to four ounces 

 of healthy urine. A similar qiianlitv was impreornaied vvitk 

 carbonic acid ga?. In the former, after forty-eliz;ht hours, 

 or more, no more than the iisi-.al nubecula ; nor could a 

 single crystal be discovered even bv a mao;nifier. In the 

 latter, an early, copious, and beautiful crvstallization. On 

 the result of this experiment, frequently repeated, ' with 

 various proportions of the raephitic alkaline water, I shali 

 afterwards have occasion to make some remarks. 



Though the mineral acids, in an uncombincd state, enter 

 not into the matter of our diet, and are no lonoer consi- 

 *lered as lithontriptics, since the notion of the earthy nature 

 of these concretions has been abandoned ; yet, as they are 

 sometimes prescribed with other indications, I thought fit 

 to extend my researches, though in a summary wav, to 

 them also. 



Expcrme?il XI. 



To sixteen ounces of urine were added eight drops of very 

 dilute sulphuric acid. To a similar quantity, two scruples 

 of citric acid, to bring them to nearly the same standard oif 

 acidity. After a very short interval, m that with citric acitl, 

 the usual appearances of transparent floating moleculag re- 

 flecting light, and gradually becoming larger, were ob- 

 served, and began to adhere to the glass ; whilst in the 

 other, alter live hours, no such appearances took place. 

 Yet, after forly-eight, here also a precipitation took place 

 of smaller crystal.-, and less in quantiiv ; for, being col- 

 lected on a filtdr, and carefully dried, they weighed onlv 

 two grains, whilst the former amounted to three. Aiul 

 this is nearly the largest proportion I ever found the above 

 quantity of healthy urine to contain. 



ExlJerlment Xlh 



As the nitrous acid is one of the most active solvents 

 f»f this matter, out of the body, I was curious to ascertain, 

 whether, in tiie very dilute state in which it must reach the 

 kidneys and bladder, (where its action must have been faci- 

 litated by the a<-tual state of solution of this substance,) it 

 would manifest its pov/ers in preveniinu' its separation. 



To tlirec ounces of urine, rendered a few hours after 

 breakfast, and, of course, scarcely acid, were added five 

 dr()ps of weak nitrous acid, which did not seem to add 

 very materially to its acescent properties. 



To a similar quantity vvcrc added four scruples of acetous 



aeid 



