514 Titration Method for Sugar in Urine 
the phosphate has formed a crystalline cake in the bottom of the 
container. 
The solution is used exactly as is Benedict’s reagent for sugar: 
To about 5 cc. in a test-tube add 5 to 8 drops of urine (not over 
0.5 ce.) and boil 1 minute, or heat in boiling water for 3 to 5 
minutes. Minute traces of sugar are indicated by various grades 
of turbidity, as in Benedict’s test; larger amounts, by unmistak- 
able cuprous oxide precipitates. The test is quite as sensitive 
and reliable as Benedict’s and a trifle more prompt. The only 
point of distinction which should be noted in the use of this re- 
agent is that unless a very marked turbidity is noted in the hot 
solutions the result must be regarded as clinically negative. The 
slight turbidity occurring after cooling represents only the re- 
ducing action of normal urine. £ | 
Quantitative Titration of Sugar an Urine-—The quantitative 
method described below for the titration of sugar in urine we 
believe to, be practical and inexpensive. 
The only solution required is an acidified copper sulfate solu- 
tion containing 60 gm. of CuSO,.5HOs, per liter.2 5 cc. of this 
solution correspond to 25 mg. of dextrose or levulose,? 45 mg. of 
anhydrous maltose, or 40.4 mg. of anhydrous lactose. The other 
necessary reagent is a dry mixture containing 100 gm. of diso- 
dium phosphate crystals (HNa,PO,.12H,O), 60 gm. of dry 
sodium carbonate (NasCO3. HO), and 30 of sodium or potassium 
sulfocyanate. These salts are mixed together in a large mortar; 
2 Pure copper sulfate solutions gradually decompose slightly giving a 
sediment of copper hydroxide, or silicate. This decomposition is presum- 
ably caused by the solvent action on the glass. To prevent it add about 
2 cc. of concentrated sulfuric acid for each 30 gm. of copper sulfate used, 
in making the standard 6 per cent copper sulfate solution. 
3 In titrations of levulose the oxidation is so rapid and complete that 
practically no attention need be paid to the time factor, so important in 
the titration of other sugars. A levulose titration can be finished in about 
2 minutes. : 
The dextrose and levulose used were Kahlbaum preparations giving 
correct polariscope values. The milk sugar was purified by recrystalli- 
zation from dilute alcohol and acetone. The maltose was a sample of 
Kahlbaum’s, but contained traces of dextrin. It was purified by dialyz- 
ing for 3 hours, and the maltose value determined by the polariscope in 
the dialysate was accepted as representing pure maltose. We have not 
been able to obtain any strictly pure maltose. 
