FORMATION OF BILE PIGMENTS. 441 



these animals after extirpation of the liver, he was able to discover them 

 on tying the ductus choledochus. The investigations of LUDWIG and 

 FLEISCHL 1 show that in the dog the bile-acids originate in the liver alone. 

 After tying the ductus choledochus, they observed that the bile constituents 

 were absorbed by the lymphatic vessels of the liver and passed into the 

 blood through the thoracic duct. Bile-acids could be detected in the 

 blood after such an operation, while they could not be detected in the 

 normal blood. But when the common bile and thoracic ducts were both 

 tied at the same time, then not the least trace of bile-acids could be 

 detected in the blood, while if they are also formed in other organs and 

 tissues they should have been present. 



From earlier reports of CLOEZ and VULPIAN, as well as VIRCHOW, the bile- 

 acids also occur in the suprarenal capsule. These claims have not been confirmed 

 by later investigations of STADELMANN and BEiER. 2 At the present time there 

 is no ground for supposing that the bile-acids are formed elsewhere than in 

 the liver. 



It has been undoubtedly proved that the bile-pigments may be formed 

 in other organs besides the liver, for, as is generally admitted, the color- 

 ing-matter ha3matoidin, which occurs in old blood extravasations, is 

 identical with the bile-pigment bilirubin (see page 301). LATSCHEN- 

 BERGER 3 also observed in horses, under pathological conditions, a 

 formation of bile-pigments from the blood-coloring matters in the tissues. 

 The occurrence of bile-pigments in the placenta also seems to depend 

 on their formation in that organ, while the occurrence of small quantities 

 of bile-pigments in the blood-serum of certain animals probably depends 

 on an absorption of these substances. 



Although the bile-pigments may be formed in other organs besides 

 the liver, still it is of first importance to know what bearing this organ 

 has on the elimination and formation of bile-pigments. In this regard 

 it must be recalled that the liver is an excretory organ for the bile-pig- 

 ments circulating in the blood. TARCHANOFF observed in a dog with 

 biliary fistula, that intravenous injection of bilirubin causes a very 

 considerable increase in the bile-pigments eliminated. This statement 

 has been later confirmed by the investigations of Vossius. 4 



Numerous experiments have been made to decide the question whether 

 the bile-pigments are only eliminated by the liver, or whether they are 

 also formed therein. By experimenting on pigeons, STERN was able 



1 Kobner, see Heidenhain, Physiologic der Absonderungsvorgange, in Hermann's 

 Handbuch, 5; Fleischl, Arbeiten aus der physiol. Anstalt zu Leipzig, Jahrgang, 9. 



2 Zeitschr. f. physiol. Chem., 18, in which the older literature may be found. 



3 See Maly's Jahresber., 16, and Monatshefte f . Chem., 9. 



4 Tarchanoff, Pfliiger's Arch., 9; Vossius, cited from Stadelmann, Der Icterus. 



