292 EARLY RESEARCHES ON THE BILE ACIDS. [BOOK II. 



ing the nature of the bile during the latter half of the 18th century, 

 viz. that it was a secretion of soap-like character. This view was 

 based on the alkaline nature of the bile, on the resinous precipitate 

 obtained on the addition of acids to it, and on the fact that a part 

 of the acids added remained in solution in combination with sodium. 



The research- It is. in the almost simultaneous observations of 

 jsofThenard*. Thenard and of Berzelius published in the first years 

 of the present century that we trace the germs of our knowledge of 

 the bile acids. Thenard experimented upon the bile of the ox. He 

 discovered the important fact that neutral and basic lead acetates 

 when added to bile cause a precipitate ; this he decomposed by 

 means of dilute nitric acid and obtained a coloured resin-like body 

 which he designated ' re'sine de la bile.' This body must have con- 

 sisted of a mixture of glykocholic and choloidic acids with colouring 

 matters. The filtrate from the first precipitate, when treated with 

 a large excess of lead acetate, yielded a second yellow precipitate, 

 from which, by the action of H 2 S, he obtained a soluble extractive 

 matter to which, because of its bitter and sweet taste, he gave the 

 name of picromel (from Tri/cpos, pungent, bitter ; and /^eXt, honey). 



The research- Shortly after Thenard's researches, Berzelius shewed 



es of Berzelius. ^^ wnen ace ti c acid is added to bile it precipitates a 

 body which had until then been considered to be albumin, but which 

 he declared to consist of mucin secreted by the gall-bladder, but 

 does not precipitate any resin-like body from bile. On adding, 

 however, sulphuric or hydrochloric acid to bile, he obtained a precipi- 

 tate consisting of a resin-like body. On decomposing this precipi- 

 tate with barium carbonate or with lead carbonate (according to the 

 acid which he had employed in the precipitation) he obtained a 

 watery solution of a substance possessing the taste of bile, and which, 

 he assumed, formed compounds with acids which were insoluble in 

 water in the presence of an excess of acid. To this supposed proxi- 

 mate principle of the bile, Berzelius applied the name of biliary 

 substance (' Diese Substanz nannte ich Gallenstoff')*. As we now 

 know, the biliary substance of Berzelius must have consisted of 

 impure glykocholic acid. 



The disco- l n the year 1826 in the celebrated work which he 

 veries * L ^ wrote in association with Tiedemann, Leopold Gmelin 3 

 andofRedten- announced the results of his researches on the bile. 

 bacher. He declared that the biliary substance of Berzelius, no 



less than the 'resine de la bile' and the picromel of 

 Thenard, consisted of mixtures of bodies. From the biliary resin 



1 Thenard, ' M6moire sur la Bile,' lu a 1'Institut le 2 floreal, an 13. Memoires de 

 Physique et de Chimie de la Societe d'Arcueil. Tome i. Paris, 1807, p. 2345. 



2 Berzelius, Forddsningar i Djurkemien, n. p. 248, Stockholm, p. 1808. Quoted 

 by Berzelius in his article ' Galle ' in Wagner's Handivorterbuch. 



3 Tiedemann und Gmelin, Die Verdauung nach Versuchen, Vol. i. (1826), p. 

 63 et seq. 



