186 UROCHEOME. 



2. Wedge-shaped opaque masses giving the 

 murexide reaction : ammonia urate. 



II. Sediment is amorphous, usually calcium phos- 

 phate. 



III. Sediment contains organised bodies, see 

 above under A III. 



Urine Oil or Essential Oil of Urine. 1. The distillate 

 from urine with sulphuric or phosphoric acid (see 

 Uromelanine) must be neutralised with sodium car- 

 bonate, evaporated to a rather low bulk, and extracted 

 repeatedly with small quantities of ether. 



2. The aqueous solution contains salts of volatile 

 acids (q.v.). 



3. Distil off the ether from the ethereal solution ; a 

 residue of essential oil will remain, with a yellowish 

 colour and a powerful urinous smell. 



4. It is little soluble in water, becoming milky when 

 mixed with it, soluble in ether and alcohol. 



5. "Warm with mercuric nitrate solution ; a purple 

 colour will be produced. 



6. Boil with silver nitrate ; no reduction will take 

 place. 



Urochrome. 1. Fresh urine is treated with excess 

 of milk of lime or baryta, allowed to stand, and 

 filtered. To the filtrate lead acetate with a little 

 ammonia is added till colourless, and the preci- 

 pitate well washed and digested with cold dilute 

 sulphuric acid till a filtered sample shows an 

 excess of sulphuric acid when tested with baryum 



