SUGAR IN URINE. 805 



titative estimation of sugar as a part of the sugar is retained by the 

 use of hydrochloric acid and blood-charcoal. According to ANDERSEN 

 the pigments and the disturbing substances can be removed by per- 

 cipitation with mercuric nitrate. It can be more simply done by treating 

 40 cc. of the urine with 10 cc. acetic acid of 50 per cent strength and 4 

 grams blood-charcoal, shaking as above described and filtering. In the 

 presence of acetic acid no sugar is taken up by the charcoal and as this 

 simple method can be used for the quantitative estimation it can therefore 

 be used in the qualitative tests for sugar. 



Fermentation Test. On using this test the process must vary accord- 

 ing as the bismuth test shows small or large quantities of sugar. If a 

 rather strong reduction is obtained, the urine may be treated with yeast 

 and the presence of sugar determined by the generation of carbon 

 dioxide. In this case the acid urine, or that faintly acidified with a little 

 tartaric acid is treated with compressed yeast, or yeast which has pre- 

 viously been washed by decantation with water. Pour this urine 

 to which the yeast has been added into a SCHROTTER'S gas burette or a 

 LOHNSTEIN'S saccharimeter (see below). As the fermentation proceeds, 

 the carbon dioxide collects in the upper part of the tube, while a correspond- 

 ing quantity of liquid is expelled below. As a control in this case two 

 similar tests must be made, one with normal urine and yeast to learn 

 the quantity of gas usually developed, and the other with a sugar solu- 

 tion and yeast to determine the activity of the yeast. According to 

 VICTOROW l the fermentation is complete after six hours at a tem- 

 perature of 34-36 C. 



If, on the contrary, only a faint reduction with the bismuth test 

 is found, no positive conclusion can be drawn from the absence of any 

 carbon dioxide or the appearance of a very insignificant quantity. The 

 urine absorbs considerable amounts of carbon dioxide, and in the presence 

 of only small amounts of sugar the fermentation test as above performed 

 may lead to negative or inaccurate results. In this case proceed in the 

 following way: Treat the acid urine, or urine which has been faintly 

 acidified with tartaric acid, with yeast whose activity has been tested 

 by a special test on a sugar solution, and allow it to stand six to twelve 

 hours at about 34-36 C. Then test again with the bismuth test, and 

 if the reaction now gives negative results, then sugar was previously 

 present. But if the reaction continues to give positive results, then it 

 shows, if the yeast is active, the presence of other reducing, unfer- 

 mentable substances. 



In performing the fermentation test care should be taken that the urine 

 be acid before as well as after fermentation. If the reaction becomes 



1 Pfliiger's Arch., 118. 



