CHAPTER XXV. 

 HEALTHY URINE. 



Contains roughly 4 p c - of solids, 2 parts of which are urae 

 and 1 part NaCl. 



Quantity in 24 hours about 1,500 cc or 521 ounces. 



Colour. Pale straw to a deeper tint. Three pigments are 

 usually recognised. (1) Urobilin, (2) Indican indoxyl 

 sulphate of potassium, and (3) Uroerythrin. The first 

 may be regarded as the normal pigment derived from 

 the blood. The second a form of indigo derived from 

 the alimentary canal, and the third as only occasionally 

 present in recognisable quantity. The latter tinges the 

 pp of urates in feverish conditions of a rose or brick 

 red colour. A chromogen of unknown nature is also 

 said to be present. 



Test for Indican. To 7 cm urine add 5 drops of HC1, mix, 

 then add nearly an equal volume of HNO 3 . The colour 

 will darken above the last acid to a red-brown 

 indigo red ? A tendency to violet indicates indigo blue. 



Odour. Urinous. 



Reaction. Usually faintly acid. Due mainly to acid sodium 

 phosphate. May become alkaline during the period of 

 digestion, due to alkaline sodium phosphate from food. 

 This alkalinity is transient. The acidity may be quanti- 

 tatively stated in terms of a normal sodium carbonate 

 solution if thought desirable. After urine has been 



