DETECTION OF PKOXIMATE PETNCIPLES 137 



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

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

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

 For colour test with sodium nitro-prusside see p. 106. 



14. Urine. Abnormal constituents. 



(a) Blood. Microscope (blood corpuscles). Spectroscope (for oxyhaemo- 

 globrn or methaemoglobin). Hsemin test. 



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

 scope. 



(c) Bile. Gmelin's test. 



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

 stringy. 



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

 in acetic acid, so distinguishing it firom phosphates. (iL) Precipitated by 

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



if) Stigar. (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 sinular slight colouration in normal urine 



due to creatinine. 



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

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



(h) Deposits. 



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



ii. Phosphates. White deposit often mixed with mucus or pus. In- 

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

 Examine microscopically for coffin-Uds of triple phosphate and star-like 

 clusters of stellar (calcium) phosphate. 



iii. Uric acid. Like cayenne pepper. Whetstone &c. crystals. Very 

 insoluble in water. Soluble in potash. Murexide test. Urine acid. 



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

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

 Murexide test. 



