486 



PRACTICAL PHYSIOLOGY 



the pigment in the acid. Examined spectroscopically a band is 

 seen in the position of the E-line, in addition to the normal band 

 at the junction of the green and blue (Fig. 277, 2). If the liquid 

 be filtered the E-band will be no longer seen. 



As regards the connection of urobilin and urochrome, it is important 

 to remember that when urochrome is acted upon by aldehyde a urobilin- 

 like substance is produced, and if urobilin be oxidised with potassium 

 permanganate a substance similar to urochrome is formed. 



aB C 



D 



Eb 



G 



FIG. 277. 



1. Acid urobilin in strong solution. 



2. Urobilin precipitated by acid from its alkaline solution and partially redissolved. The 

 so-called E-band spectrum. 



3. Uroerythrin. 



4. Uroerythrin in pink urate sediments. 



The pink colour possessed by a deposit of urates is due to another 

 pigment Uroerythrin. This pigment is never excreted in large amount, 

 but it possesses in high degree a colouring power. If a pink urate 

 deposit be dissolved in warm water the urates may be precipitated 

 by saturation with ammonium chloride carrying clown the pigment. 

 This may now be extracted with alcohol, and on shaking the alcoholic 

 solution with chloroform to which one drop of acetic acid has been 

 added the pigment passes into the chloroform. It now gives the 

 spectrum seen in Figure 277, 3. If the pink urate deposit be simply 



