URINE. 109 



CONJUGATE S0 3 . 



To 75 c.c. of urine in a beaker add an equal volume of 

 water; acidulate with about 10 drops of acetic acid, heat 

 to boiling and a,dd 10 c.c. of the BaCl 2 solution. Place the 

 covered beaker in a cool place for about 24 hours. The 

 precipitate is then collected on a filter and in the filtrate 

 and combined washings the S0 3 is determined as outlined 

 under total S0 3 . In this case the result corresponds to 

 the S0 3 of the conjugate sulphates. 



ORGANIC SULPHUR. 



Evaporate 50 c.c. of urine down to .dryness, add the 

 fusion mixture and fuse with an alcoholic flame until a white 

 residue remains. Take this up with hot water strongly 

 acidulated with HC1. Determine the amount of S0 3 present 

 in this solution and calculate the amount for the 24 hours, 

 from which may be subtracted the total S0 3 which has been 

 previously estimated in another sample of the same urine. 

 The difference will give the organic sulphur expressed as 

 S0 3 in the 24-hour sample. 



PHOSPHATES = P 2 5 . 



Phosphorus is present in the urine to the greatest extent 

 as phosphoric acid combined with bases, but a small quantity 

 (2-2.5 per cent) exists as organic P.; e.g., glycerophosphoric 

 acid, lecithin, etc. It has been stated that the amount of 

 this latter form of phosphorus is a true indication of the ni- 

 trogenous metabolism taking place in the body. The phos- 

 phoric acid phosphorus is expressed as P 2 5 , and during 

 24 hours about 1.5-3.5 grms. (average 2.5 grms.) P 2 6 



