734 URINE. 



ment is not preformed in the urine, but is produced from its chromogen (indol 

 acetic acid) when the urine is treated with hydrochloric acid alone. The urine 

 becomes red. Urorosein differs from indirubin essentially by the same properties 

 as skatol, with which, according to some, it is identical (see above). 



Nephrorosein is a pigment described by V. ARNOLD 1 which is closely'related to 

 urorosein and which, like this, is produced from a chromogen when the urine is 

 treated with nitric acid or with concentrated hydrochloric acid and a little sodium 

 nitrite solution. Nephrorosein is soluble in amyl alcohol and gives a spectrum 

 with a band between 6 and F, reaching from 6 to a little beyond the middle between 

 b and F. It is changed by the action of light and finally gives a band between 

 D and E, near E. The new pigment thus obtained is called (3-urorosein to dif- 

 ferentiate it from the ordinary urorosein, a-urorosein. The nephrorosein has not 

 been observed in normal urines but only in certain pathological cases. 



The pigment obtained by DE JAGER by precipitating the urine with HC1 and 

 formol seems to be related to urorosein and nephrorosein. According to ELLINGER 

 and FLAMAND 2 urorosein belongs probably, like skatol-red, to the group of tri- 

 indyl methane pigments prepared by them from /3-indol aldehyde by boiling in 

 acid solution. Probably the leucobase HC.(C 8 H 6 N) 3 , which gives the red pigment, 

 HO.C 1 (C 8 H 6 N) 3 is produced by condensation. 



Aromatic Oxyacids. In the putrefaction of proteins in the intes- 

 tine, paraoxyphenyl-acetic acid and paraoxyphenyl-propionic acid are 

 formed from tyrosine as an intermediate step, and these in great part 

 pass unchanged into the urine. The quantity of these acids is usually 

 very small. They are increased under the same conditions as the phenols, 

 especially in acute phosphorus poisoning, in which the increase is con- 

 siderable. A small portion of these oxyacids is also combined with 

 sulphuric acid. 



Besides these two oxyacids which regularly occur in human urine 

 we sometimes have other oxyacids in urines. To these belong homo- 

 gentisic acid in alcaptonuria, oxyhydroparacoumaric acid, found by BLENDER- . 

 MANN in the urine on feeding rabbits with tyrosine, gallic acid, which, 

 according to BAUMANN, S sometimes appears in horse's urine, and kynu- 

 renic acid (oxyquinolincarboxylic acid), which up to the present time 

 has been found only in dog's urine. Although all these acids do not 

 belong to the physiological constituents of the urine, still they will be 

 treated in connection with these. 



Paraoxyphenylacetic Acid, C 8 H 8 3 , C 6 H 4 \ , and p-Oxyphenyl- 



X CH 2 .f~ 



are 



/OH 



.COOH 



/OH 



propionic Acid (Hydroparacoumaric Acid), C 9 Hi 3 , C 6 H/ , 



\CH 2 .CH 2 COOH 



crystalline and are both soluble in water and in ether. The one melts at 148 C. 

 and the other at 125 C. Both give a beautiful red coloration on being warmed 

 with MILLON'S reagent. 



1 Zeitschr. f. physiol. Chem., 61 and 71. 



2 de Jager, Zeitschr. f. physiol. Chem., 61; Ellinger and Flamand, ibid., 62. 



3 Blendermarm, Zeitschr. f. physiol. Chem., 6, 267; Baumann, ibid., 6, 193. 



