278 THE URINE. 



an elimination of from 3 to 6 per cent, in an amount of urine 

 varying between 3000 and 6000 c.c. may be regarded as moderate. 



Tests for Sugar. Simple tests by means of which glucose can be 

 demonstrated directly in the urine as such are, unfortunately, not 

 available. Other sugars, it is true, enter into consideration only 

 under exceptional conditions, but if it is desired to prove that the 

 substance which gives the common sugar reactions is actually glu- 

 cose, a more detailed examination is necessary. Some of these tests, 

 moreover, may be simulated by substances which are not carbo- 

 hydrates, and deductions as to the presence or absence of sugar are 

 hence only warrantable when these can be excluded. If albumins 

 are present, they must first be removed. 



NYLANDER'S TEST. This test is to be preferred to the more 

 common one of Trommer, as the reagent does not react with uric 

 acid, kreatinin, or homogentisinic acid. With many of the conju- 

 gate glucuronates, however, a reduction is observed, and it is hence 

 necessary to eliminate this source of error when a positive reac- 

 tion is obtained, or to apply additional tests in which this possi- 

 bility does not enter into consideration. 



The reagent is prepared as follows : 4 grammes of the tartrate 

 of potassium and sodium, together with 2 grammes of subnitrate of 

 bismuth and 10 grammes of sodium hydrate are placed in 90 c.c. 

 of water. The solution is heated to the boiling-point, filtered on 

 cooling, and is then ready for use. It is kept in a dark-colored 

 bottle. 



A few cubic centimeters of the urine are treated with the reagent, 

 in the proportion of 11 : 1, and boiled, when in the presence of 

 sugar a reduction of the subnitrate of bismuth to bismuthous oxide, 

 or even to the metallic form, occurs. As a consequence the mixture 

 assumes a grayish, dark-brown, or black color, and on standing the 

 precipitated oxide or metal settles to the bottom together with the 

 earthy phosphates. 



FEHLING'S TEST. This is merely a modification of the older 

 Trommer's test. The reagent consists of two solutions, viz., one 

 containing 34.64 grammes of copper sulphate in 500 c.c. of water, 

 while the other is prepared by dissolving 173 grammes of tartrate 

 of potassium and sodium and 125 grammes of caustic soda in a like 

 amount of water. Before using, equal parts of the two solutions 

 are mixed and diluted with four times as much water. A few cubic 

 centimeters of the resulting reagent are boiled and treated with a 

 small amount of the urine, when in the presence of sugar yellow 

 cuprous hydroxide or red cuprous oxide separates out, and on stand- 

 ing settles to the bottom. After the addition of the urine the solu- 

 tions should no longer be boiled, but may be held near the flame 

 for a few moments. Unless this precaution is taken, fallacious 

 results are often obtained, as uric acid, and kreatinin more especially, 

 may cause a partial reduction of the copper solution on prolonged 

 boiling. The test at best is open to many objections. Conjugate 



