UKOCHEOME. 187 



chloride and hydrochloric acid. At this point filter 

 the whole, shake the filtrate with baryum carbonate to 

 remove the sulphuric acid, add a little baryta water, 

 pass carbonic acid through the liquid and filter again. 

 Precipitate the solution with mercuric acetate, wash 

 the precipitate of urochrome mercury very thoroughly 

 with cold and hot water, decompose it by sulphuretted 

 hydrogen, filter, shake the filtrate with a little fresh 

 silver oxyde to remove hydrochloric or kryptophanic 

 acid, filter ; again decompose by sulphuretted hydro- 

 gen, and evaporate the filtrate to dryness in vacuo 

 over sulphuric acid. A yellow uncrystallisable mass 

 of urochrome remains. 



2. Urochrome is easily soluble in water with a 

 yellow colour, very little soluble in alcohol, soluble in 

 ether, and can thereby be separated from kryptophanic 

 acid, which is insoluble in ether. 



3. To the solution in water add lead or mercuric 

 acetate : a flaky yellowish precipitate will fall. 



4. Add silver nitrate : a gelatinous precipitate solu- 

 ble in nitric acid, will form. 



5. Add mercuric nitrate : a white precipitate, pale 

 flesh-coloured on boiling, will be produced. 



6. The aqueous solution on standing becomes red 

 and deposits resinous flakes, containing uromelanine, 

 uropittine, omicholine, and omicholic acid (q.v ). This 

 decomposition is hastened by boiling and by acids. 



7. Treat acidified extract of urine by ether, and 

 distil the latter. Precipitate the residue by basic lead 

 acetate, decompose by hydrothian, and treat urochrome 

 as above. 



