386 APPENDIX 



Fermentation Test. This is the surest test for sugar in the urine. It will show 

 the presence of 0.05% of glucose. Instead of the Einhorn apparatus one may be 

 extemporized by taking a 50 c.c. cylinder, filling it to overflowing with the urine 

 which has previously been rubbed up with a piece of compressed yeast the size of a 

 hazel-nut. The urine should be made acid with tartaric acid to prevent ammoniacal 

 decomposition with the formation of CO 2 . A small 3-in. test-tube is filled with the 

 yeast-treated urine and dropped mouth downward into the 50 c.c. cylinder. The 

 apparatus is incubated for twenty-four hours and the presence of gas in the closed 

 end of the test-tube shows that sugar was present. A control to determine that the 

 yeast does not contain sugar is advisable. To utilize this test as a quantitive one, 

 first accurately take the specific gravity of the urine; then add the yeast and 

 fill the test-tube and cylinder as directed above. Next pour off or pipette off the 

 urine exactly to the 50 c.c. mark. Incubate for twenty-four to forty-eight hours 

 and make up the loss by evaporation, with distilled water. After the urine has 

 cooled down to room temperature the contents of tube and cylinder are thoroughly 

 mixed (the small tube having been withdrawn with a pair of forceps), then filtered 

 to remove the sediment of yeast and then brought to the exact original volume of 

 50 c.c. with distilled water to make up the loss by evaporation. (If there should be 

 doubt as to the completion of the fermentation of the glucose a qualitative test for 

 sugar can be made.) The specific gravity is again taken and the difference between 

 this and the first reading multiplied by 0.23. Example: Specific gravity of unfer- 

 mented urine, 1.030, that of urine after incubation, 1.022. Difference, 8X0.23 = 

 1.84%. 



It is advisable to have two good urinometers, one to register from 1000 to 1025, 

 a second to register from 1025 to 1050. 



Benedict's New Method for Quantitative Determination of Sugar in Urine. 



The solution for quantitative work has the following composition: 



Copper sulphate (pure crystallized) 18.0 c.c. 



Sodium carbonate crystallized (100 grams of anhydrous 



salt will answer) 200 . o gm. 



Sodium or potassium citrate 200 . o gm. 



Potassium sulphocyanate 125.0 gm. 



5 % potassium ferrocyanid solution 5.0 c.c. 



Distilled water to make total volume of 1000.0 c.c. 



With the aid of heat dissolve the carbonate, citrate and sulphocyanate in enough 

 water to make about 800 c.c. of the mixture, and filter if necessary. Dissolve the 

 copper sulphate separately in about 100 c.c. of water and pour the solution slowly 

 into the other liquid, with constant stirring. Add the ferrocyanid solution, cool and 

 dilute to exactly one liter. Of the various constituents, the copper salt only need be 

 weighed with exactness. Twenty five c.c. of the reagent are reduced by 50 mg. of 

 glucose. 



Sugar estimations are conducted as follows: The urine, 10 c.c. of which should 

 be diluted with water to 100 c.c. (unless the sugar content is believed to be low), is 

 poured into a 50 c.c. burette up to the zero mark. Twenty-five c.c. of the reagent 

 are measured with a pipette into a porcelain evaporating dish (25-30 cm. in diameter), 



