156 THE DIGESTIVE FLUIDS. 



Perfectly fresh hepatic bile, in contradistinction to that which is 

 found in the gall-bladder, contains only one pigment, bilirubin, from 

 which all other forms are derived. Such bile is of a golden-yellow 

 <x>lor, while bladder-bile usually presents an olive-brown color, owing 

 to the simultaneous presence of its nearest oxidation -product, bili- 

 verdin. A grass-green color is observed when the latter predomi- 

 nates or is exclusively present. 



Bilirubin. Bilirubin is now known to result from the decompo- 

 sition of haematin, and normally constitutes a specific product of the 

 activity of the hepatic cells. It appears, however, that the power 

 of transforming the blood-pigment into bilirubin is common to other 

 tissues as well, if we regard the haematoidin of Virchow, which is 

 so often found in old extravasations of blood, as identical with bili- 

 rubin. That this is actually the case seems now undoubted. Under 

 normal conditions, however, the liver is apparently the only organ 

 of the body in which the formation of bilirubin takes place. 

 Whether or not the final dissolution of disintegrating red corpuscles 

 .also occurs at this place has not been decided, but the liver is 

 manifestly capable of retaining the haemoglobin which is thus set 

 free. If a moderate amount of a solution of haemoglobin is injected 

 into the bloodvessels of an animal, an increased elimination of 

 bilirubin results, while the blood-pigment does not appear in the 

 urine. If larger amounts are injected, the resulting bilirubin ap- 

 parently cannot be removed with sufficient rapidity through the 

 biliary ducts. Resorption of the pigment then takes place through 

 the lymph-vessels, jaundice results, and the bile-pigment appears in 

 the urine. If excessive amounts of haemoglobin finally are injected, 

 the liver is manifestly incapable of retaining all the pigment which 

 reaches the organ, jaundice results, and both the bile-pigment and 

 the blood-pigment appear in the urine. Even in such extreme 

 cases the remaining tissues of the body do not participate in the 

 formation of bilirubin. This has been conclusively demonstrated 

 by Minkowski and Naunyn. These observers have shown that while 

 in normal geese poisoning with hydrogen sulphide, which causes 

 an extensive dissolution of the red corpuscles, invariably leads to 

 jaundice and the appearance of bile-pigment in the urine, the 

 previous removal of the liver prevents such an occurrence, and 

 results in simple haemoglobinuria. In mammals such crucial tests 

 unfortunately cannot be applied, but there is no reason to suppose 

 that different conditions there exist. The possible occurrence of a 

 haematogenic icterus, in contradistinction to a hepatogenic icterus, is 

 thus rendered extremely improbable, and it is scarcely warrantable 

 to point to the development of bilirubin from blood-pigment in the 

 tissues of the organs, as indicating the possibility of such a trans- 

 formation in the circulating blood. 



Of the manner in which this transformation is effected in the liver 

 we know nothing. We may imagine, however, that the oxyhsemo- 

 globin is here first decomposed into its albuminous component 



