URINE: QUANTITATIVE ANALYSIS. 



367 



FIG. 117. 



thorough mixing of the fluids and stand the tube aside for 24 hours. 

 Creatinine, resin acids, etc., are precipitated in this method, and for 

 this and other reasons it is not as accurate as the coagulation method. 

 It is, however, extensively used clinically. 



Calculation. The graduations on the albuminometer indicate 

 grams of protein per liter of urine. Thus, if the protein precipi- 

 tate is level with the figure 3 of the graduated 

 scale this denotes that the urine examined con- 

 tains 3 grams of protein to the liter. To express 

 the amount of protein in per cent simply move 

 the decimal point one place to the left. In the 

 case under consideration the urine contains 0.3 

 per cent of protein. 



II. Dextrose. 



i. Fehling's Method. Place 10 c.c. of the 

 urine under examination in a 100 c.c. volumetric 

 flask and make the volume up to 100 c.c. with 

 distilled water. Thoroughly mix this diluted 

 urine, by pouring it into a beaker and stirring 

 with a glass rod, then transfer a portion of it 

 to a burette which is properly supported in a 

 clamp. 



Now place 10 c.c. of Fehling's solution 1 in a 

 small beaker, dilute it with approximately 40 c.c. 

 of distilled water, heat to boiling, and observe 

 whether decomposition of the Fehling's solution 

 itself has occurred as indicated by the production 

 of a turbidity. If such turbidity is produced the 

 Fehling's solution is unfit for use. Clamp the 

 burette containing the diluted urine immediately 

 over the beaker and carefully allow from 0.5 to i 

 c.c. of the diluted urine to flow into the boiling 

 Fehling's solution. Bring the solution to the boil- 

 ing-point after each addition of urine and continue 

 running in the urine from the burette, 0.5-1 c.c. at a time, as indi- 

 cated, until the Fehling's solution is completely reduced, i. e., until 

 all the cupric oxide in solution has been precipitated as cuprous oxide. 

 This point will be indicated by the absolute disappearance of all blue 

 color. When this end-point is reached note the number of cubic centi- 



1 Directions for the preparation of Fehling's solution are given in a note at 

 the bottom of page 308. 



ESBACH'S ALBUMI- 

 NOMETER. (Ogden.) 



