314 COLOURING MATTERS. 



comparison of the writings of Berzelius*, Schererf, HeinJ, 

 Platner, and others. 



Berzelius also found in the bile a substance occurring in small 

 reddish yellow crystals, soluble in alcohol, to which he has given 

 the name of bilifulmn. I have obtained it in solution, but have 

 never succeeded in isolating it in the solid state ; singularly enough, 

 I have often found it in the bile precipitated with neutral and basic 

 acetate of lead ; hence it appears either not to be precipitated by 

 these metallic salts, or (which is more probable) to redissolve in 

 an excess of the basic salt. 



Composition. With our present ignorance of bile-pigment in 

 its pure unchanged state, it is not to be wondered at that its 

 elementary composition is still unknown. Bile-pigment has been 

 analysed both by Scherer and Hein, but it is obvious from their 

 analyses that they have examined very different substances, and 

 Scherer has especially shown that the pigment which he examined 

 loses much carbon and hydrogen by the action of air, alkalies, and 

 acids. From 7 to 9^- of nitrogen has been found in bile-pigment. 



Preparation. Till recently the ordinary mode of preparing 

 bile-pigment consisted in the extraction, by water and ether, of 

 biliary calculi, consisting for the most part of this constituent ; the 

 residue thus obtained does not, however, generally possess the 

 power of dissolving in alcohol, for (as Bramson|| has very cor- 

 rectly shown, and as any unprejudiced observer may easily con- 

 vince himself) it exists in a state of insoluble combination with 

 lime, even in those concretions which for the most part consist of 

 cholesterin. 



The mode of investigation which Brarnsom adopted, and which 

 I. have often repeated, appears to me to leave no doubt regarding 

 the correctness of his views, which moreover receive further con- 

 firmation from the analyses of biliary concretions made by Schmid^f 

 and Wackenroder.** 



Berzelius prepares biliverdin from ox-gall by precipitating the 

 alcoholic extract with chloride of barium; the precipitate is first 

 washed with alcohol, and afterwards with water, and then de- 



* Lehrb. d. Ch. Bd. 9, S. 281-286. 

 t Ann. d. Ch. u. Pharm. Bd. 53, S. 377- 

 t Journ. f. pr. Ch. Bd. 40, S. 47-56. 

 Ann. d. Ch. u. Pharm. Bd. 51, S. 115. 

 Jl Zeitschr. f. rat. Med. Bd. 4, S. 193-208. 

 f Arch, der Pharm. Bd. 41, S. 291-293. 

 ** Ibid. S. 294-296. 



