CHAP. IV.] EARLY RESEARCHES ON THE BILE 'ACIDS. 293 



he succeeded in separating, however, a crystalline acid to which he 

 ve the name of cholic acid x and which was the acid to which 

 hinann afterwards applied the name by which we now know it, 

 viz. glykocholic acid. Amongst a large number of hypothetical 

 roximate principles, the discovery of which depended upon errors 

 f method or of interpretation, Gmelin placed a crystalline body 

 which he had separated from Thenard's biliary resin ; this crystal - 

 ine body, which he believed to exist in a free condition in the bile, 

 ,nd which he designated biliary asparagine (' Gallenasparagin '), is 

 he body we now know as taurine. Its composition was unknown to 

 melin, who was not even aware that it contained the element 

 sulphur. It is a remarkable fact that both Demarcay and Dumas 

 who subsequently made ultimate analyses of taurine, having failed 

 to test it for sulphur, obtained results which led to the formula 

 C 2 H 7 N0 5 1>2 . It was only in 1846 that Redtenbacher 3 discovered 

 the presence of sulphur in taurine, and shewed that the empirical 

 ormula C 2 H 7 N0 5 must be replaced by C 2 H 7 NSO 3 . 



Demarcay's The next enquirer whose researches we are called 



investigations. U p 0n to not i ce was Demarcay. His work formed the 

 basis of an independent report to the French Academy by Dumas 

 and Pelouze 2 , the former of whom submitted to ultimate analysis 

 some of Demarcay's products. This observer concluded that the bile 

 contains the sodium salt of a single acid to which he gave the name 

 of choleic acid (acide choleique), which was analysed by Dumas as 

 well as by himself and to which the empirical formula C^H^NaO^ 

 was assigned. When boiled with acids he believed that this acid 

 split up into an acid which he termed choloidic acid, C 38 H 60 7 , and 

 into taurine, C 4 H 14 N 2 10 (C = 6). When boiled with caustic alkalies 

 holeic acid was, according to Demarcay, split up into ammonia and 

 cholic acid, C 4 oH 7 20 10 . Demarcay's choleic acid was, in reality, 

 taurocholic acid in which he failed to find the sulphur, as he like- 

 wise did in taurine. In spite of his mistakes in these particulars, 

 Demarcay was the first to recognise the conjugate nature of a bile 

 acid and to shew that taurocholic acid splits up, when heated with 

 acids, into a nitrogenous body, and into a non-nitrogenous acid. 



The researches, of Adolf Strecker. 



It is to the long continued and masterly researches of Adolf 

 Strecker that we owe the greater part of our knowledge of the bile 

 acids and of their compounds, and the description of these bodies 

 which will follow is based in great part upon his work. His first 



1 H. Demarcay, ' Ueber die Natur der Galle.' Annalen der Pharmacie, Vol. xxvn. 

 {1838), pp. 270291. 



2 Pelouze und Dumas, ' Bericht iiber vorstehende Abhandlung an die Akademie in 

 Paris (Auszug).' Annalen der Pharmacie, Vol. xxvu. (1838), pp. 292295: also in 

 Comptes Rendus, 1838, no. 8, 2 me seance. 



3 Jos. Redtenbacher, 'Ueber die Zusammensetzung des Taurins.' Annalen der 

 CJiem. ii. Pharm., Vol. LVII. (1846), pp. 170177. 



