1046 SECRETED FLUIDS SUBSERVIENT TO DIGESTION. 



tated carbonate of lead, for the purpose of combining its sul- 

 phuric acid and oily acids, and the greater proportion of the 

 alcohol then distilled off. The liquid thus concentrated is 

 filtered from the precipitate of lead salts, freed from lead in 

 solution by sulphuretted hydrogen, filtered and evaporated to 

 dryness in a water-bath. The transparent, yellow, bitter mass 

 which remains, and which was formerly distinguished by Ber- 

 zelius as biliary matter, is composed of bilin and fellinic 

 acid. 



The last product is dissolved in water and digested with 

 finely pulverised oxide of lead, by which it forms a plaster-like 

 mixture of fellinate and cholinate of lead, and the bilin re- 

 mains undissolved. The filtered solution of bilin is evaporated 

 to dryness ; and to separate foreign matters, the mass is again 

 dissolved in alcohol, filtered and evaporated to dryness. What 

 remains is bilin. (Grundriss der Organischen chemie von Dr. 

 F. Wohler.) 



Bilin is a translucent, colourless, inodorous mass, without 

 crystallization, having a bitter and at the same time somewhat 

 sweetish taste. It contains nitrogen, and is decomposed by 

 heat, with the formation of ammoniacal products. Water and 

 alcohol dissolve it in all proportions ; it is insoluble in ether. 

 Its solution in water is not precipitated by acids, chlorine or 

 metallic salts. Bilin is a readily alterable substance; by boiling 

 with caustic alkali, it is decomposed and resolved into cholic 

 acid and ammonia. It is decomposed by acids into five dif- 

 ferent substances, namely ammonia, taurin, feUinic and cholinic 

 acids, and dyslysin ; a decomposition which may occur in the 

 bile of the living body. 



When bilin is dissolved and digested in dilute hydrochloric 

 acid, an oily substance presents itself, consisting of bilin in 

 combination with fellinic and cholinic acids, which by farther 

 digestion changes into a resin-like mass, insoluble in water. 

 The solution then contains sal ammoniac and taurin ; while the 

 resinous mass consists of fellinic and cholinic acids with dyslysin. 

 The two former may be dissolved out of the resinous mass by 

 cold alcohol. 



Dyslysin remains undissolved in the last operation, as a resin- 

 like mass. It dissolves, although with some difficulty, in boiling 



