518 Titration Method for Sugar in Urine 
described above except that the counting of the drops is 
omitted. 
The sugar titration described above has been adapted to the 
use of test-tubes instead of evaporating dishes, beakers, or flasks, 
and it has been adapted to the use of undiluted urine. The ob- 
jection to the traditional dilution of urine to a sugar concen- 
tration of 0.5 to 1 per cent is that it cannot be properly made 
except on the basis of a preliminary sugar titration. (In the 
hands of medical students with a limited supply of measuring 
utensils the most frequent cause of gross errors in sugar determ1- 
nations is one or another error or carelessness in connection with 
the dilution.) Our sugar titration can, of course, also be made with 
sugar solutions containing only one-half of 1 per cent of sugar 
and can therefore be made with sugar urines diluted to such a 
sugar concentration. It can also be adapted to the use of flasks 
instead of test-tubes, but only at the expense of chemicals. For 
those who prefer to use flasks, we recommend that the standard 
copper solution contain 3 per cent instead of 6 per cent copper 
sulfate. For 10 cc. of this solution (corresponding to 25 mg. of 
dextrose) 10 gm. of the dry alkaline salt mixture should be taken. 
If much less salt than that prescribed is used the white cuprous 
sulfocyanide is hydrolyzed and traces of red cuprous oxide begin 
to appear and the end-point of the titration becomes less readily 
visible. We believe that very few who have once become familiar 
with the use of test-tubes in sugar titrations will go back to the 
use of flasks, beakers, or other vessels. 
Sugar in Urine. 
No. of urine. New method. Benedict’s method. By the polariscope. 
per cent per cent per cent 
1 1.8 1.78 1.81 
2 4.16 4.2 4.12 
3 2.94 2.94 2.99 
4 1.41 1.43 1.39 
5 0.98 1.05 0.98 
6 6.66 0G 6.63 
7 1.56 1.54 1.52 
8 2.84 2.96 2.89 
9 4.5 4.56 4.45 
10 3.62 3.74 3.68 
