261 



tion. On the result of this experiment, freqviently repeat- 

 ed, with various proportions of the mephitic alkaline wa- 

 ter, I shall afterwards have occasion to make some re- 

 marks. 



Though the mineral acids, in an uncombined state, en- 

 ter not into the matter of our diet, and are no longer 

 considered 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 

 wa35) t9,;)J?,em also. 



EXPERIMENT 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 of acidity. After a very short interval, in that 

 with citric acid, the usual appearance of transparent float- 

 ing moleculse reflecting light, and gradually becoming lar- 

 ger, were observed, and began to adhere to the glass; 

 whilst in the other, after five hours, no such appearances 

 took place. Yet, after forty-eight, here also a precipitation 

 took place, of smaller crystals, and less in quantity; for, 

 being collected on a filter, and carefully dried, they weighed 

 only two grains; whilst the former amounted to three. And 

 this is nearly the largest proportion I ever found the above 

 quaiitity of healthy }}fiif>e, ,tjO cfmtain. 



' yiftfi, ,^ l^ 1 1 EXPERIMENT 



