ICTERUS 407 



hemolytic agents cause icterus is explained by the fact that 

 on account of the large amounts of free hemoglobin brought to 

 the liver, excessive amounts of bile-pigment are formed, which 

 render the bile so viscid that it blocks up the fine bile capillaries ; 

 on account of the low pressure at which bile is secreted, a slight 

 obstruction of this kind is sufficient to stop entirely the outflow 

 of bile, which then enters the lymphatics of the liver and also 

 the blood-stream itself. 1 It is also possible that the hemolytic 

 poisons injure the liver-cells so much that the minute intra- and 

 intercellular bile capillaries become disorganized, and permit of 

 escape of bile into the lymph-spaces and its absorption into the 

 blood-vessels. Swelling of the degenerated liver-cells may also 

 be an important factor in the occlusion of the bile capillaries, 

 and swelling of the living cells of the bile capillaries may also 

 coexist. 



Toxicity of Bile. In any event, we must appreciate that 

 in icterus not only are abnormally large quantities of bile-pig- 

 ment present in the blood, but also the other less conspicuous 

 constituents of the bile. The relative toxicity of the bile-pig- 

 ments and the bile salts is not as yet uniformly agreed upon. 



Bile=pigments. Bouchard 2 and others have claimed that 

 the bile-pigments are far more toxic than the bile salts, which 

 is contradicted by Rywosch and others. As Rywosch found 

 that doses of 0.6 gram of bile-pigments per kilo had almost no 

 effect on rabbits, it is doubtful if the amount absorbed by a 

 patient with icterus can have serious effects, since it is estimated 

 that the normal daily excretion of bile-pigment in man averages 

 but about 0.5 gram. The amount of pigment in the blood in 

 icterus is correspondingly minute. 3 



Bile salts are undoubtedly toxic, generally producing depres- 

 sion of the central nervous system, with resulting coma and 

 paralysis ; they are also decidedly toxic to cells of all sorts, 

 causing hemolysis and marked destruction of tissue-cells. Small 

 quantities of bile salts stimulate the central end of the vagus, 

 and larger amounts influence the heart itself; hence in icterus 

 we observe a slowing, and often an irregularity, of the pulse, 

 and the blood pressure is lowered. Although there has been 



1 See Mendel and Underbill, Amer. Jour. Physiol., 1905 (14), 252. 



2 Literature and discussion by Stadelmann, Zeit. f. Biol., 1896 (34), 57. 



3 A series of analyses by Gilbert and others (Compt. Kend. Soc. Biol., 1905 

 (38), July 7, et seq.) gave the following results: Normal blood-serum contains 

 0.027-0.08 gram bilirubin per liter, which is the source of the normally pro- 

 duced urobilin ; in obstructive icterus they found 0.068 gram of bilirubin per 

 liter, or about 0.2 gram in the blood of the entire body ; in biliary cirrhosis 

 0.33 gram per liter, in icterus neonatorum 0.2 to 0.5 gram, in pneumonia 0.068 

 gram was found. 



