URINE. 335 



PENTOSES. 



We have two distinct types of pentosuria, i. e., alimentary pen- 

 tosuria, resulting from the ingest ion of large quantities of pentose- 

 rich vegetables such as prunes, cherries, grapes or plums, and 

 fruit juices, in which condition the pentoses appear only temporarily 

 in the urine ; and the chronic form of pentosuria, in which the output 

 of pentoses bears no relation whatever to the quantity and nature of 

 the pentose content of the food eaten. In occurring in these 

 two forms, pentosuria resembles glycosuria (see page 306), but it is 

 definitely known that pentosuria bears no relation to diabetes mel- 

 litus and there is no generally accepted theory to account for the 

 occurrence of the chronic form of pentosuria. The pentose de- 

 tected most frequently in the urine is arabinose, the inactive form 

 generally occurring in chronic pentosuria and the laevorotatory 

 variety occurring in the alimentary type of the disorder. 



EXPERIMENTS. 



1. Tollens' Reaction. To equal volumes of urine and hydro- 

 chloric acid (sp. gr. 1.09) add a little phloroglucin and heat the 

 mixture on a boiling water-bath. Pentose, galactose, or glycuronic 

 acid will be indicated by the appearance of a red color. To differen- 

 tiate between these bodies examine by the spectroscope and look 

 for the absorption band between D and E given by pentoses and 

 glycuronic acid, and then differentiate between the two latter bodies 

 by the melting-points of their osazones. 



2. Orcin Test. Place equal volumes of urine and hydrochloric 

 acid (sp. gr. 1.09) in a test-tube, add a small amount of orcin, 

 and heat the mixture to boiling. Color changes from red, through 

 reddish-blue to green will be noted. When the solution becomes 

 green it should be shaken in a separatory funnel with a little amyl 

 alcohol, and the alcoholic extract examined spectroscopically. An 

 absorption band between C and D will be observed. 



FAT. 



When fat finds its way into the urine through a lesion which 

 brings some portion of the urinary passages into communication 

 with the lymphatic system a condition known as chyluria is es- 

 tablished. The turbid or milky appearance of such urine is due 

 to its content of chyle. This disease is encountered most frequently 



