ICTERUS 405 



amount under physiological conditions. (2) With the pigment 

 accumulation there occur degeneration and death of the contain- 

 ing cells and consequent interstitial inflammation, notably of 

 the liver and pancreas, which become the seat of inflammatory 

 changes accompanied by hypertrophy of the organ. (3) When 

 chronic interstitial pancreatitis has reached a certain grade of 

 intensity, diabetes ensues, and is the terminal event in the 

 disease. 



ICTERUS 1 



Pigmentation of the tissues of the body in jaundice depends 

 upon the presence in them of bile-pigments, which have been 

 formed in the liver and reabsorbed either into the lymph or 

 blood (or both). Although a pigment that seems to be chem- 

 ically identical with bilirubin (hematoidin) may be formed from 

 hemoglobin liberated on the breaking up of red corpuscles, yet 

 this is probably never formed in sufficient amounts outside of 

 the liver to give rise to general icterus. However, the local 

 greenish-yellow pigmentation occurring in the vicinity of extrav- 

 asations of blood, due to hematoidin formation, may be looked 

 upon as a " local jaundice." 



Bile-pigments. Bilirubin is of a reddish-yellow color, and it is 

 the chief pigment of human bile. Its formula is C 16 H 18 N 2 O 3 , and its 

 relation to hematin, from which it is formed, is shown by the following 

 formula, which, according to Nencki and Sieber, expresses the manner 

 in which blood pigment is converted into bilirubin by the liver under 

 normal conditions, and into hematoidin (its isomer) in the tissues and 

 fluids of the body in pathological conditions : 



C 32 H 32 N 4 4 Fe + 2H 2 -= 2C 16 H 18 N 2 O 3 + Fe. 

 (hematin) (hematoidin or bilirubin) 



Bilirubin is not soluble in water, but dissolves in the alkaline body 

 fluids as a soluble compound, "bilirubin alkali." It is very slightly 

 soluble in ether, benzene, carbon disulphide, amyl-alcohol, fatty oils, 

 and glycerin, but is more soluble in alcohol and in chloroform. 



Biliverdin, C 16 H 18 N 2 O 4 , as its formula indicates, is an oxidation 

 product of bilirubin. Bilirubin in alkaline solutions will oxidize into 

 biliverdin merely on exposure to the air, and the change from yellow to 

 green of icteric specimens when placed in oxidizing solutions (e. g., 

 dichromate hardening fluids) is due to the formation of the green bili- 

 verdin. Biliverdin is the chief pigment of the bile of carnivora, but it 

 is also present in varying amounts in human bile. 



The various other biliary pigments, namely, bilifuscin, biliprasin, 

 choleprasin* bilihumin, and bilicyanin, are probably not normal constit- 

 uents of bile, but are oxidation products of bilirubin, and are found 



1 Literature by Stadelmann, " Der Icterus," Stuttgart, 1891 ; Minkowski, 

 Ergebnisse der Pathol., 1895 (2), 679. 



2 See Kiister, Zeit. physiol. Chem., 1906 (47), 294. 



