263 



A cloudiness and transparent granular precipitation took 

 place, followed by the formation of extremely minute gra- 

 velly concretions, which, even after two days standing, did 

 not assume so red a tinge as that with vegetable acids. 

 This may, probably, depend upon some action of this 

 ^acid upon'.tiie.uceei or colouring matter: but, as to the 

 smallness of the crystals, that evidently depends upon the 

 more speedy precipitation, throwing them down before 

 they can assume their natural size, and leaving but a 

 shade of difference between the crystalline and pulverulent 



deposits. ''B ()P, H99 



-■'^^' " EXPERIMENT XIV. 



. .From the above,' then, we are satisfied, that the vege- 

 ta;ble and mineral acids cause a premature separation and 

 crystallization of the lithic contents of recent healthy urine: 

 but)it;jnay''be observed, that this only takes place, under 

 circumstances not at all applicable to the living system; 

 viz. a much inferior temperature; and, in some instances, 

 •a contact with the atmospheric air: two powerful promot- 

 ing causes of. crystallization in general, but more especially 

 of the less soluble salts. To determine, therefore, this most 

 .essential point : ' 



■ . ,To six. ounces of cold but recent urine, (in a well closed 

 phial,) were added five drops of very dilute nitrous acid, 

 which were placed on a sand bath: temperature varying 

 from 80 to about 100 degrees at most. The same quantity, 

 with similar precautions, but without , addition, was laid 



L 1 2 aside, 



