THE URINE. 371 



with a little lead peroxide. This choletelin acts like urobiliu, but 

 that obtained from bilirubiu by the action of nitric acid does not. 

 'Bodies similar to urobilin have also been obtained by HOPPE- 

 SEYLER, by the reduction of haematin and haemoglobin with zinc and 

 hydrochloric acid; by LE NOBEL, by treating an acid-alcoholic or 

 alkaline solution of haematoporphyrin with tin or zinc; and lastly 

 by NENCKI and SIEBEE, by treating haematoporphyrin with zinc 

 and hydrochloric acid. From the observations of LE NOBEL and 

 NEDTCKI and SIEBER it follows that these coloring matters arti- 

 ficially prepared from the blood-coloring matters are not identical, 

 even though they are closely related from an optical standpoint. 

 It must be left undecided whether these bodies are identical with 

 each other or with the urinary urobilin, or if the observed difference 

 is only due to a contamination with other bodies. 



Because of our imperfect knowledge of the urobilin of the urine 

 and the UROBILINOIDIN (this name has been given by LE NOBEL to 

 the substance artificially prepared by him) it is difficult to say 

 anything positive in regard to the occurrence of urobilin in the 

 urine in disease. During the absorption of large blood extravasa- 

 tions, as also in diseases connected with destruction of the blood- 

 corpuscles or of the appearance of methaemoglobin in the blood- 

 plasma, the urine becomes dark in color, which generally depends 

 upon an increased elimination of urobilin. The question whether 

 it depends on an increased elimination of urinary urobilin or, as is 

 more probable, upon the urobilinoidin produced from the blood- 

 coloring matters is still doubtful. In icterus the elimination of 

 urobilin is often increased, and indeed cases occur in which the 

 urobilin is almost the only coloring matter which can be detected 

 in icteric urines (UROBILINICTERUS). In these cases we are probably 

 dealing with a urobilinoid substance produced from the bile-coloring 

 matters. 



The urobilin obtained from a fever urine is, according to 

 JAFFE, amorphous, red, dingy-red, or reddish yellow, according to 

 the method of preparation. It dissolves easily in alcohol, amyl- 

 alcohol, and chloroform, but less readily in ether. It is less 

 soluble in water, but the solubility is augmented in the presence of 

 a neutral salt. It may be precipitated from a solution saturated 



