DETERMINATION OF SUGAR. 



765 



The sugar in milligrams is directly obtained from the amount of hydroxyl- 

 amine solution used by referring to the following reduction table: 1 



For every TO cc. hydroxylamine solution used more than given in the table 

 between 49.00-15.00, subtract 0.1 milligram from the corresponding sugar value 

 and 0.2 milligram between 15.00-1.0. 



For exact determinations of sugar the method as suggested by ALLIHN 

 and modified by PFLUGER 2 is the best suited. 



The TITRATION ACCORDING TO KNAP? depends on the fact that mercuric 

 cyanide in alkaline solution is reduced to metallic mercury by dextrose. The 

 titration liquid should contain 10 grams of chemically pure dry mercuric cyanide 

 and 100 cc. of caustic-soda solution of a specific gravity of 1.145 per liter. When 

 the titration is performed as described below (according to WORM-MULLER and 

 OTTO), 20 ec. of this solution should correspond to exactly 0.05 gram of dextrose. 

 If the process is carried out in other ways, the value of the solution is different. 



In this titration also, the quantity of sugar in the urine should be between 

 and 1 per cent, -and the extent of dilution necessary be determined by a preliminary 

 test. To determine the end-reaction as described below, the test for the excess 

 of mercury is made with sulphuretted hydrogen. 



In performing the titration allow 20 cc. of KNAP.P'S solution to flow into a 

 flask and dilute with 80 cc. of water, or when the urine contains less than 0.5 

 per cent of sugar use only 40-60 cc. After this heat to boiling arid allow the diluted 

 urine to flow gradually into the hot solution, at first 2 cc., then 1 cc., then 0.5 cc., 



1 This table is given with the permission of the publisher, Julius Springer, Berlin. 



2 Pfliiger's Arch., 66. 



