358 



ANALYSIS OF URINE. 



[CH. XIH. 



impossible, before the titration is completed. Add a few drops of 

 the saturated solution of phenol phthalein and titrate the hot solu- 

 tion with the standard soda. The end point is quite sharp. 

 Calculation, i cc. of o-i N. soda iff 4-0 mg. SO 8 . 



419. Total sulphates by the benzidine method. Measure 

 25 cc. of the urine into the Erlenmeyer flask, add 2 to 2*5 cc. of the 

 hydrochloric acid and 20 cc. of distilled water. Place a funnel in 

 the neck of the flask and boil gently for 20 minutes. Cool thoroughly 

 under the tap, add 100 cc. of the benzidine hydrochloride, and 

 proceed as directed above. 



Ethereal Sulphates. 



The difference between the result of the analysis in Ex. 419 and 

 that of Ex. 418 is the ethereal sulphate. 



Total Sulphur and Neutral Sulphur. 



The urine can be oxidised by Benedict's method (Ex. 417) and 

 the residue dissolved in hydrochloric acid. Before the benzidine 

 method is applied the excess of free hydrochloric acid must be reduced 

 by the addition of soda until the solution is only 

 just acid to congo red paper. The calculation 

 for neutral sulphur is explained in Ex. 417. 



L. Albumin. 



420. The estimation of albumin by 

 Esbach's method. 



Fill the albuminometer to the mark U 

 with urine. Add Esbach's reagent (Ex. 14) 

 to the mark R. Stopper the tube, and invert 

 it slowly several times to mix the fluids. Allow 

 the tube to stand upright for 24 hours. 



Calculation. The graduations on the albumino- 

 meter indicate grams, of albumin per litre. 



Fig. 47. Esbach's 

 albuminometer. 



421. The estimation of albumin by Scherer's method. 



Measure 50 cc. of urine into a beaker. Place it on a water bath 

 and raise the temperature to 50 C. Add i per cent, acetic acid, 



