URINE. 293 



in appendicitis, carcinoma of the liver, catarrhal icterus, pernicious 

 anaemia and in cases of poisoning by antifebrin, antipyrin, pyridin, 

 and potassium chlorate. In general it is usually increased when 

 blood destruction is excessive and in many disturbances of the liver. 

 It is markedly decreased in phosphorus poisoning. 



EXPERIMENTS. 



1. Spectroscopic Examination. Acidify the urine with hydro- 

 chloric acid and allow it to remain exposed to the air for a few 

 moments. By this means if any urobilinogen is present it will be 

 transformed into urobilin. The urine may now be examined by 

 means of the spectroscope. If urobilin is present in the fluid the 

 characteristic absorption-band lying between b and F will be ob- 

 served (see Absorption Spectra, Plate II). It may be found neces- 

 sary to dilute the urine with water before a distinct absorption- 

 band is observed. This test may be modified by acidifying 10 c.c. 

 of urine with hydrochloric acid and shaking it gently with 5 c.c. of 

 amyl alcohol. The alcoholic extract when examined spectro- 

 scopically will show the characteristic urobilin absorption-band. 

 (Note the Spectroscopic examination in the next experiment.) 



2. Ammoniacal-Zinc Chloride Test. Render some of the urine 

 ammoniacal by the addition of ammonium hydroxide, and after 

 allowing it to stand a short time filter off the precipitate of phos- 

 phates and add a few drops of zinc chloride solution to the filtrate. 

 Observe the production of a greenish fluorescence. Examine the 

 fluid by means of the spectroscope and note the absorption-band 

 which occupies much the same position as the absorption-band of 

 urobilin in acid solution (see Absorption Spectra, Plate II). 



3. Gerhardt's Test. To 20 c.c. of urine add 3-5 c.c. of chloro- 

 form and shake well. Separate the chloroform extract and add to 

 it a few drops of iodine solution (I in KI). Render the mixture 

 alkaline with dilute solution of potassium hydroxide and note the 

 production of a yellow or yellowish-brown color. The solution 

 ordinarily exhibits a greenish fluorescence. 



4. Wirsing's Test. To 20 c.c. of urine add 3-5 c.c. of chloro- 

 form and shake gently. Separate the chloroform extract and add 

 to it a drop of an alcoholic solution of zinc chloride. Note the 

 rose-red color and the greenish fluorescence. If the solution is 

 turbid it may be rendered clear by the addition of a few c.c. of 

 absolute alcohol. 



5. Ether- Absolute Alcohol Test. Mix urine and pure ether 



