174 ESSENTIALS OF CHEMICAL PHYSIOLOGY 



(g) Creatinine. Take 100 c.c. of urine : add 5 c.c. of a saturated solution 

 of sodium acetate and 20 c.c. of a saturated solution of mercuric chloride- 

 Filter. Set the filtrate aside for twenty-four hours, and a spherical mercury 

 compound of creatinine crystallises out. Examine this with a microscope. 



For colour test with sodium nitro-prusside see p. 142. 



14. Urine. Abnormal constituents. 



(a) Blood. Microscope (blood corpuscles). Spectroscope (for oxy haemo- 

 globin or methaemoglobin). Haemin test. 



(6) Blood pigment may be present without blood corpuscles. Spectro- 

 scope. 



(c) Bile. Gmelin's test. Hay's sulphur test. 



(d) Pus. White deposit. Microscope (pus cells). Add potash ; it becomes 

 stringy. 



(e) Albumin, (i.) Precipitated, if acid, by boiling ; precipitate insoluble 

 in acetic acid, so distinguishing it from phosphates, (ii.) Precipitated by 

 nitric acid in the cold, (iii.) Precipitated by picric acid. 



(/) Sugar, (i.) Brown colour with potash and heat (Moore's test), (ii.) 

 Ferments with yeast, (iii.) Reduces Fehling's solution, (iv.) Urine has a 

 high specific gravity, (v.) Add picric acid, potash, and boil ; the urine 

 becomes a dark opaque red ; the similar slight coloration in normal urine is 

 due to creatinine. 



(g) Acetone. For colour test see p. 168. 



(h) Mucus. Flocculent cloud ; may be increased by acetic acid ; soluble 

 in alkalis. A little mucus in urine is not abnormal. 



(i) Deposits. 



i. Examine microscopically for blood corpuscles, pus cells, crystals, &c. 



ii. Phosphates. White deposit often mixed with mucus or pus. Insoluble 

 on heating; soluble in acetic acid. Urine generally alkaline. Examine 

 microscopically for coffin-lids of triple phosphate and star-like clusters of 

 stellar (calcium) phosphate. 



iii. Urates. Pink deposit, usually amorphous; may be mixed with 

 envelope crystals of calcium oxalate. Deposit soluble on heating urine. 

 Murexide test. 



iv. Uric acid. Deposit like cayenne pepper. Microscope. Tests as 

 above. 



