URINE. 07 



INDICAN= POTASSIUM INDOXYL SULPHATE, 

 C.H/ NH ^H 



The following tests are based upon the oxidation of the 

 indican to indigo, and the solvent action of chloroform upon 

 the latter. 



(a) Jaffe's Test. To about 10 c.c. of urine add 2 or 3 c.c. 

 of chloroform and mix well with an equal volume, 10 c.c., of 

 concentrated HC1. Then add drop by drop, shaking well 

 between each drop, a concentrated solution of chloride of 

 lime. The indigo is dissolved by the chloroform. Note the 

 color changes. 



(6) Obermayer's Test. Perform the test in the same man- 

 ner except instead of concentrated HC1 and lime add an equal 

 volume of Obermayer's reagent. 



(c) Hammarsteris Test. The same test, using Hammar- 

 sten's reagent. Compare results. 



c 



OXALIC ACID, 



\OH 



Oxalic acid is present in the normal urine in the form of 

 calcium oxalate, which is held in solution by the presence of 

 the acid phosphates. Frequently the salt separates out in 

 crystalline form (see sediments) and then lays the foundation 

 for renal and vesical calculi. The quantity averages about 

 30 mg. for 24 hours. In certain conditions which are not 

 well understood the amount is largely increased (oxaluria). 

 The oxalic acid originates in part from the oxalates ingested 



