96 URINARY CALCULI. 



solution ammonia in excess ; a white crys- 

 talline precipitate falls ; Ammonia magnesium 

 phosphate. In case the melted residue is in- 

 soluble in acetic acid, treat with hydrochloric 

 acid; it dissolves. Add to the solution am- 

 monia ; a white precipitate indicates Calcium 

 . phosphate. 



b. It does not melt; moisten the residue with 

 water, and test its reaction with litmus paper ; 

 it is not alkaline. Treat with hydrochloric 

 acid, it dissolves without effervescence. Add 

 to the solution ammonia in excess , white pre- 

 cipitate; Calcium phosphate. Treat the cal- 

 culus with acetic acid; it does not dissolve. 

 Treat the residue after heating with acetic 

 acid, it dissolves with effervescence ; Calcium 

 oxalate. Treat the original calculus with acetic 

 acid, it dissolves with effervescence; Calcium 

 carbonate. 



B. The calculus on being heated does not leave a 

 fixed residue. Treat a portion of the calculus with 

 nitric acid, evaporate and expose to ammonia vapour 

 as before. 



I. A pink colour is developed. 



a. Mix a portion of the powdered calculus with a 

 little lime, and moisten with a little water;- 

 ammonia is evolved and a red litmus paper 

 suspended over the mass is turned blue; 

 Ammonium urate. 



b. No ammonia; Uric acid. 



