THE URINE. 373 



ammonia, and then treated with zinc-chloride solution. This new 

 .precipitate is washed free from chlorine with water, boiled with 

 alcohol, dried, dissolved in ammonia, and this solution precipitated 

 with sugar of lead. This precipitate, which is washed with water 

 and boiled with alcohol, is decomposed by alcohol containing sul- 

 phuric acid, the filtered alcoholic solution is mixed with f vol. 

 chloroform, diluted with water, and shaken repeatedly, but not too 

 energetically. The urobilin is taken up by the chloroform. This 

 last is washed once or twice with a little water and then filtered, 

 leaving the urobilin, which is purified from a contaminating red 

 coloring matter by means of ether. 



According to JAFFE, the coloring matter can be directly precipitated from 

 a fever urine rich in urobiliu by ammonia and zinc chloride, and this precipi- 

 tate treated as above. MEHY faintly acidities the urine with sulphuric acid 

 (1-2 grms. per litre), then saturates with ammonium sulphate, washes the pre- 

 cipitate on a filler with an acidified ammonium-sulphate solution, presses the 

 filter, and extracts the coloring matter with absolute alcohol at a gentle heat 

 after the addition of a few drops of ammonia. MACMUNN precipitates the urine 

 with sugar of lead and basic lead acetate, decomposes the precipitate with 

 acidified alcohol, dilutes the solution with water, shakes with chloroform, 

 evaporates this last, and dissolves the residue repeatedly with chloroform. 

 The method of preparation, according to MACMUNN, is the same for both 

 urobilins, the normal and the febrile. 



The color of the acid or alkaline solution, the beautiful fluores- 

 cence of the ammoniacal solution treated with zinc chloride, and 

 the absorption-bands of the spectrum, all serve as means of detect- 

 ing urobilin. In fever urines the urobilin may be detected directly 

 or after the addition of ammonia and zinc chloride by its spectrum. 

 It may also be detected sometimes in normal urine directly or after 

 the urine has stood exposed to the air until the chromogen has 

 been converted into urobilin. If it cannot be detected by means of 

 the spectroscope, then the urine may be treated with a mineral acid 

 and shaken with ether. The ethereal solution may be, directly or 

 after concentration, tested with the spectroscope. It is often bet- 

 ter to dissolve the residue, after the evaporation of the ether, in 

 absolute alcohol, and use this for the spectroscopic investigation. 

 According to SALKOWSKI, the urobilin may be directly extracted 

 by gently shaking with ether free from alcohol. If the urobilin 

 cannot be detected by the above-described methods, then precipi- 

 tate the urine with basic lead acetate, decompose the precipitate 

 with acidified alcohol, test this solution or extract the coloring 

 matter by diluting with water and shaking with chloroform. 



The urochrom (THUDICHUM) seems to be a mixture of several bodies. 

 Uroerythrin is that coloring matter which often colors the urinary sediment 

 (sedimentum lateritium) beautifully red. It occurs especially in fevers and 

 other diseases, but it is not found in the urine of perfectly healthy persons. 



