URINE 453 



2. Robin's Reaction. Acidify 10 c.c. of urine with about 15 drops of con- 

 centrated hydrochloric acid. Upon allowing the acidified urine to stand, a rose-red 

 color will appear if urorosein is present. 



3. Nencki and Sieber's Reaction. To 100 c.c. of urine in a beaker add 10 c.c. 

 of 25 per cent sulphuric acid. Allow the acidified urine to stand and note the ap- 

 pearance of a rose-red color. The pigment may be separated by extraction with 

 amyl alcohol. 



NEPHROROSEIN 



This pigment is closely related to urorosein 1 and like urorosein it is 

 produced from a chromogen when the urine is treated with nitric acid 

 or with concentrated hydrochloric acid and a little sodium nitrite 

 solution. It is sometimes called /3-urorosein to differentiate it from the 

 true urorosein which is termed a-urorosein. Nephrorosein occurs only 

 in pathological urines. 



UROCHROMOGEN 



This is the chromogen of urochrome, the normal urinary pigment 

 (see Chapter XXI). It is claimed that the uro chromogen reaction of the 

 urine is an aid to prognosis and diagnosis of pulmonary tuberculosis. 

 .Urochromogen is not present in normal urine. Its presence in patho- 

 logical urine is due probably to faulty oxidation, i.e., failure to oxi- 

 dize the chromogen to urochrome. Urochromogen may be detected by 

 oxidizing it to urochrome by means of potassium permaganate. In 

 this process a certain antecedent of Urochromogen is also oxidized 

 to urochrome. Whereas the diazo reaction (see page 454) is also 

 given by urines containing Urochromogen, it is claimed that the diazo 

 reaction does not show the presence of the precursor of Urochromogen. 

 Hence the Urochromogen reaction is said to be more constant and uni- 

 form in its appearance. 



EXPERIMENT 



Urochromogen Reaction (Weisz). 2 Fill a test-tube a little less than one- 

 third full of urine, dilute it with 2 volumes of distilled water and mix thoroughly. 

 Pour one-half the diluted urine into another tube and to one of the tubes add 3 

 drops of a i per cent solution of potassium permanganate. Shake the tube 

 thoroughly. In the presence of Urochromogen a yellow tint will appear in the 

 tube to which permanganate was added. 



The reaction is due to the oxidation of Urochromogen to urochrome, 

 and is believed to be of value as an aid in prognosis and diagnosis of 



1 Arnold: Zeit. physiol. Chem., 71. 



2 Weisz: Munch, med. Woch., 58, 1348, 191 1. 

 Vitri: Semana Medica, 20, No. 28, 1913. 

 Heflebower: Am. Jour. Med. Sci., 143, 221, 1912. 

 Metzger and Watson: Jour. Am. Med. Ass'n., 62, 1886, 1914. 

 Pignacca: Gazetta d. Osp. e delle Clin., 25, 353, 1911. 

 Ferrannini: Riforma med., 31, 479, 1915. 



