442 THE LIVER. 



to detect bile-pigments in the blood-serum five hours after tying the 

 biliary passages alone, while after tying all the vessels of the liver and also 

 the biliary passages, no bile-pigments could be detected either in the 

 blood or the tissues of the animal, which was killed 10-24 hours after 

 the operation. MINKOWSKI and NAUNYN 1 also found that poisoning 

 with arseniureted hydrogen produces a liberal formation of bile-pig- 

 ments, and the secretion, after a short time, of a urine rich in biliverdin 

 in previously healthy geese. In geese with extirpated livers this does 

 not occur. 



With experiments on dogs, WHIPPLE and HOOPER 2 found after intra- 

 venous injection of blood-corpuscles of the same animal heemolyzed 

 with water, that a transformation of the haemoglobin into bile-pigments 

 occurred with the same rapidity in normal animals as with animals with 

 Eck fistulas, or with such a fistula and the hepatic artery ligatured. The 

 formation of bile-pigments also occurred on removing the liver, spleen 

 ;and abdomen from the circulation, as well as by circulation through the 

 head and thorax. A transformation of haemoglobin into bile-pigments, 

 at least in dogs, can take place easily without the medium of the liver 

 and these experimenters suggest the possibility that the endothelial 

 cells are here active. 



No such experiments can be carried out on mammalia, as they do 

 not live long enough after the operation; still there is no doubt that this 

 organ is the chief seat of the formation of bile-pigments under physiolog- 

 ical conditions. 



In regard to the materials from which the bile-acids are produced, 

 it may be said with certainty that the two components, glycocoll and 

 taurine, which are both nitrogenized, are formed from the protein bodies. 

 The close relation of taurine to the cystine group of the protein mole- 

 cule has been especially shown by the investigations of FREIDMANN, 

 (see Chapter III), and recently v. BERGMANN S has shown by feeding 

 dogs with sodium cholate and cystine that the animal body can trans- 

 form cystine into taurine, and that the taurine of the bile originates 

 from the proteins of the food. In regard to the origin of the non-nitro- 

 genized cholic acid, which was formally considered as originating from 

 the fats, nothing is positively known; to all appearances it is from 

 proteins. 



The blood-coloring matters are considered as the mother-substances 

 of the bile-pigments. If the identity of hsematoidin and bilirubin was 



1 Stern, Arch. f. exp. Path. u. Pharm., 19; Minkowski and Naunyn, ibid., 21. 



2 Journ. of exp. Med., 17. 



3 Hofmeister's Beitrage, 4. See also Wohlgemuth, Zeitschr. f. physiol. Chem., 40. 



