256 UROERYTHRIN. UROH^EMATOPORPHYRIN. 



of this one but frequently mixed with other pigments which are 

 derived either from the fluid originally operated upon, or are decompo- 

 sition products resulting from the action of the reagents employed \ 

 The final solution of the questions raised above will only be supplied 

 by a purely chemical investigation of the several substances under 

 discussion; such an investigation would however be one of extreme 

 difficulty. 



Thudichum considered that normal urine contains only one pigment, which he 

 called urochrome 2 . Maly regarded this as the same as urobilin 3 . More recently 

 Thudichum has upheld his former views 4 . 



2, Uroerythrin. 



This is a pigment of which but little is known. It is regarded 

 as the colouring substance of certain bright red (pink) urinary 

 deposits and as possibly occurring in the highly coloured urines 

 of rheumatism &c. It appears to be an amorphous reddish sub- 

 stance, with an acid reaction, slowly soluble in either water, 

 alcohol or ether 5 . Treated with caustic alkalis it turns green, more 

 particularly when in the solid form. In alcoholic solution obtained by 

 boiling pink urates with alcohol it shows two ill-defined absorption 

 bands between D and F. 6 



3. Urohsematoporphyrin. 



This pigment was first described by Mac Munn (under the 

 name of urohsematin) as occasionally occurring in certain patho- 

 logical urines as of acute rheumatism, Addison's disease &c. and 

 to it he gave the present name from certain resemblances of 

 its spectra to those of hsematoporphyrin 7 . It is obtained from 

 urine by the method employed for the separation of urobilin, or 

 artificially by the action of reducing agents on haematin, this 

 being the supposed source of its origin in the body. It is soluble 

 in either alcohol, ether, benzol or chloroform. In acid alcoholic 

 solution it shows three absorption bands, one narrow adjoining D on 

 the red side of this line, one half way between D and E and one 

 between b and F closely resembling the band of urobilin. There is 



1 Thus Vierordt has shown that if the urinary pigments are precipitated by the 

 acetates of lead and extracted from this by absolute alcohol acidulated with oxalic 

 acid, the coloured solution thus obtained possesses optical properties quite different 

 from those of the original urine, a result which indicates that the pigments have 

 been considerably changed during extraction. Die quantitat. Spectralanalyse, 1876, 

 S. 96. 



2 Brit. Med. Jl. No. 201, 1864, p. 509. 



3 Liebig's Ann. Bd. CLXIII. (1872), S. 90. 



4 Jl. Chem. Soc. Ser. 2, Vol. xin. (1875), pp. 397, 401. 



5 Heller, in his Archiv. (2) Bd. in. (1854), S. 361. 



6 Mac Munn, Proc. Roy. Soc. Vol. xxxv. (1883), pp. 132, 370. 



7 Jl. of Physiol. Vols. vi. (1884), p. 36 ; x. (1889), p. 73. 



