250 ORIGIN OF BILE-PIGMENTS. 



into further details on the now undoubted but once disputed derivation 

 of the bile pigments from the colouring-matter of blood (see 477). 



The starting point for this view was the discovery and description 

 of hsematoidin crystals by Yirchow (see p. 240) as occurring in old 

 blood-clots in parts of the body remote from the liver and in which it 

 was inconceivable that they could have arisen by any process other 

 than a gradual formation from the pigment of the red corpuscles, 

 followed as this was by proofs of the identity of haematoidin and 

 bilirubin. This was followed 1 by experiments on the injection of 

 bile-salts into the blood and an accompanying output of bile-pigments 

 in the urine, to which the true significance was subsequently attached 

 by Kiihne, namely that the pigments arose from a conversion of 

 haemoglobin set free from the corpuscles under the solvent action of 

 the bile-salts. This he confirmed by injections of hsemoglobin. in 

 solution 2 . These views were however opposed on the basis of similar 

 experiments in which it was stated that either no bile-pigments 

 appeared in the urine as the result of injections of haemoglobin into 

 the vascular system, or that if they did, they were due merely to an 

 accumulation of that small amount which is frequently present in the 

 urine of dogs 3 . But the careful subsequent experiments of Tarchanoff, 

 in which he endeavoured to avoid many obvious sources of error 

 present in those of Naunyn and Steiner, are more usually regarded as 

 having afforded definite and conclusive confirmation of the earlier 

 views 4 . This observer further found a considerably increased amount 

 of bile-pigments in the bile collected during the experiments, and came 

 to the conclusion that the conversion of blood- into bile-pigments takes 

 place in the blood vessels, a part being excreted in the urine, while 

 the larger part passes out in the bile. He showed in confirmation of 

 earlier experiments 5 that the liver is extremely active in excreting 

 bilirubin injected into the blood vessels; practically the whole of it 

 passes out in the bile 6 . The relationships thus indicated receive 

 further confirmation from the observation that in many pathological 

 conditions of the horse, bile-pigments are copiously found in its tissues 

 and transudations accompanied by blood-pigments, and that solutions 

 of haemoglobin when injected into the subcutaneous tissue of this 

 animal become after a few days partially converted in situ into 



1 Frerichs u. Staedeler, Miiller's Arch. Jahrg. 1856, S. 55. 



2 Virchow's Arch. Bd. xiv. (1858), S. 310. Cf. Physiol. Chem. 1868, S. 89. 



3 Naunyn, Arch. f. Anat. u. Physiol. Jahrg. 1868, S. 401. Steiner, Ibid. 1873, 

 S. 160. Contain full references to all then existing literature. 



4 Pfluger's Arch. Bd. ix. (1874), Sn. 53, 329. 



5 Feltz et Hitter, Jn. de VAnat. et de la Physiol. 1870, p. 315. Cf. Vossius, Arch. 

 f. exp. Path. u. Pharmakol. Bd. xi. (1879), S. 426. 



6 See later Stadelmann, Ibid. Bd. xv. (1882), S. 237 and (in connection with the 

 next reference) Bd. xxvn. (1890), S. 93. 



