URINE AND ITS CONSTITUENTS. 735 



Estimation by means of the polariscope furnishes the quickest method ; 

 the details cannot be given here. 



Other carbohydrates in urine. Laevulose is rarely present in the 

 urine; in almost all of the cases dextrose is also presen t(diabetes). 

 Laevulosuria should be suspected when a urine reduces copper solu- 

 tions, rotates polarized light to the left or not at all, and shows no 

 Ia3vorotation after being fermented. 



Lsevulose reduces copper and bismuth solutions, ferments with 

 yeast, is laevorotatory, and forms the same osazone with phenyl- 

 hydrazine as is formed by dextrose. 



Maltose is very rarely present in urine. Such urines show a 

 higher percentage of sugar with the polariscope than with Fehling's 

 solution. 



Lactose occurs in the urine of lactating women, and occasionally 

 in the urine of persons on an exclusive milk diet. It gives a delayed 

 and incomplete Fehling test, reduces Nylander's solution, does not 

 ferment with yeast, rotates polarized light to the right. While it 

 forms a yellow osazone with phenyl-hydrazine, the amount present in 

 the urine is rarely sufficient to give a positive test. 



Pentoses, C 5 H 10 O 5 , occur in many fruits and vegetables as complex 

 carbohydrates, known as pentosanes. When taken into the body the 

 pentosanes are split and pentose is excreted in the urine. Consid- 

 erable pentose is found in the urine of persons addicted to the use 

 of morphine. Pentoses owe their chief importance to the similarity 

 of their reactions to those of glucose. Normally, the quantity of 

 pentose in the urine is not such as to interfere with the reactions for 

 sugar. 



Pentoses reduce Fehling's and bismuth solutions ; they are dextrorotatory ; 

 with phenyl-hydrazine they form a crystalline compound, melting between 

 153 and 158 C. (307 and 317 F.). Pentoses do not ferment with yeast, and 

 are characterized by responding to Tollen's orcin reaction. This is made by 

 adding 3 c.c. of a saturated solution of orcin in hydrochloric acid to 5 c.c. of 

 urine previously decolorized with boneblack. In the presence of pentose a 

 green color develops on heating, beginning at the top and gradually extending 

 through the mixture. 



Glycuronic acid, CHO.(CHOH) 4 .CO 2 H. Glycuronic acid occurs 

 in normal urine in minute amount. It is an oxidation product of 

 glucose, and is usually present in the form of the conjugated glycu- 

 ronates, i. e., glycuronic acid linked to aromatic bodies (phenol, cresol, 

 etc.). It is increased after the taking of camphor, chloral, menthol, 

 and other substances, which produce aromatic substances in the urine 



