300 THE URINE. 



sorbinose), but is also obtained with those polysaccharides which 

 yield fructose on hydrolysis, viz., cane-sugar, raffinose, inulin, etc. 



Maltose. Maltose together with glucose was found on one occa- 

 sion in the urine of a patient supposedly the subject of pancreatic 

 disease. Its recognition is essentially dependent upon the forma- 

 tion of its osazon, and the identification of the latter by its melting- 

 point. 



Dextrin. That traces of dextrin are found in the urine under 

 normal conditions has been pointed out. Larger amounts have been 

 observed in the case of a diabetic patient, where the substance 

 apparently took the place of glucose. Of its origin nothing definite 

 is known, but it is likely that in health the substance gains entrance 

 to the circulation in a more or less accidental way, and is then, 

 of course, eliminated at once. It is now regarded as identical with 

 the animal gum of Landwehr. 



Pentoses. That traces of pentoses may occur in the urine under 

 normal conditions has been stated. As has been shown, the 

 pancreas contains a nucleoproteid which yields a very large 

 amount of pentose on decomposition, and one might imagine 

 that the normal pentose of the urine might possibly be refer- 

 able to this source. Neuberg, however, has shown that the 

 two are not identical. The urine pentose (arabinose) is optically 

 inactive, while the pentose of the pancreas is /-xylose. The normal 

 pentoses, no doubt, are referable to the ingestion of such articles of 

 food as prunes, cherries, grapes, beer, wine, etc., in which arabinose 

 occurs preformed. As in the case of glucose, the power to assimi- 

 late pentoses seems to vary with different individuals, and here, as 

 there, a digestive pentosuria can be artificially produced. In 

 diabetes the power to oxidize the pentoses may be much impaired, 

 and, very curiously, the largest quantities have been observed in 

 morphin habitu&s. 



The individual pentoses which have thus far been encountered in 

 the urine are arabinose, xylose, and rhamnose. They all reduce 

 Fehling's solution and give rise to osazons with phenylhydrazin. 

 The melting-points of the resulting compounds, however, are differ- 

 ent from those of the common hexosazons (see page 295). In the 

 amounts, however, in which they are usually present no reactions 

 are obtained in this manner. The fermentation test is negative. 

 Xylose and rhamnose turn the plane of polarization to the right, 

 while arabinose is optically inactive. 



To demonstrate the presence of pentoses in the urine the follow- 

 ing test of Tollens is employed : 



ORCIN TEST (as described by Bial). 4-5 c.c. of 'the reagent 

 (500 c.c. of 30 per cent, hydrochloric acid, 1 gramme of orcin, and 

 25 drops of liquor ferri sesquichloridi) are heated to boiling ; the tube 

 is removed from the flame and a few drops to 1 c.c. of urine added. 

 With pentose urine there is immediately a fine green coloration. 

 Normal and diabetic urines do not give the reaction, nor do urines 



