PRACTICAL EXERCISES 435 



7. Normal organic constituents. Sometimes quantitative estimation of 

 urea or total nitrogen in fever, and in diabetes and Bright's disease. 



8. Chemical examination for abnormal organic constituents, especially 

 albumin and sugar. 



Albumin. (i) Heat some of the urine in a test-tube to boiling. A 

 precipitate insoluble on addition of a few drops of acetic acid consists of 

 coagulable proteid. A precipitate soluble in acetic acid consists of earthy 

 phosphates. 



(2) Heller's test. Put some strong nitric acid in a test-tube and run on 

 to it some urine. A white ring indicates proteid. 



A quantitative estimation may be made by the meihod of Roberts and 

 Stolnikow (p. 430). 



Sugar. (i) Trommer's test. (Fehling's solution may be used.) If the 

 result is indecisive : 



(2) Phenyl-hydrazine test (p. 431). 



(3) In case of doubt confirm by yeast test. 



A quantitative estimation may be made with Fehling's solution or the 

 polarimeter. 



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