URINE 443 



for glycuronates the urine may first be subjected to a polariscopic examination, 

 then fermented and a second polariscopic examination made. The sugar being 

 dextrorotatory and fermentable and the glycuronates being levorotatory and 

 non-fermentable the second polariscopic test will show a levorotation indicative 

 of conjugate glycuronates. 



3. Reduction-Polariscopic Test. Test the urine by Fehling's test. If 

 positive try the Resorcinol-HCl reaction for fructose. If negative test the optical 

 activity. Levorotation indicates glycuronates. 



PENTOSES 



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

 resulting from the ingestion 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 re- 

 sembles glycosuria (see page 413), but it is definitely known that pen- 

 tosuria bears no relation to diabetes mellitus and there is no generally 

 accepted theory to account for the occurrence of the chronic form of 

 pentosuria. The pentose detected most frequently in the urine is 

 arabinose, the inactive form generally occurring in chronic pentosuria 

 although keto-pentose 1 may occur in some cases. The levorotatory 

 variety occurs in the alimentary type of the disorder. 



EXPERIMENTS 



1. Orcinol-Hydrochloric Acid Reaction (Bial). 2 To 5 c.c. of BiaPs reagent 3 

 in a test-tube add 2-3 c.c. of urine and heat the mixture gently until the first 

 bubbles rise to the surface. 4 Immediately or upon cooling the solution becomes 

 green and a flocculent precipitate of the same color may form. 



This test is believed to be more accurate than the original orcinol 

 test. It is claimed that urines containing menthol, kreosotal, etc., 

 respond to the old orcinol reaction, but not to BiaPs. If so desired 

 the osazone of the pentose may be formed, then distilled with hydro- 

 chloric acid and the distillate tested by BiaPs test (Jolles). 



2. Phloroglucinol-Hydrochloric Acid Reaction (Tollens). To equal volumes 

 of urine and hydrochloric acid (sp. gr. 1.09) add a little phloroglucinol and heat 

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



1 Levene and La Forge: Jour. Biol. Chem., 18, 319, 1914. 



2 Bial: Deut. med. Woch., 28, 252, 1902. 



3 Orcinol 15 grams. 



Fuming HC1 5 grams. 



Ferric chloride (10 per cent) 20-30 drops. 



4 The test may also be performed by adding the urine to the hot reagent. No further 

 heating should be necessary if pentose is present. 



