CHAP, iv.] PLATTNER'S CRYSTALLISED BILE. 291 



is at first produced and, as the quantity of ether added is increased, 

 a white amorphous precipitate, alls to the bottom and adheres, in 

 part, to the walls of the vessel in which the precipitation occurs. If 

 the process of drying of the bile has been complete and the alcohol 

 and ether subsequently employed anhydrous, the snow-white precipi- 

 tate in the course of some hours or some days exhibits tufts of 

 beautiful needles 1 . To this crystalline precipitate the name of 

 Plattner's crystallised bile is given. It is composed of the sodium 

 salts of glykocholic and of taurocholic acids. 



The bile of all animals contains either a glykocholic or a tauro- 

 cholic acid or a mixture of these acids. Glykocholic acid, on the 

 one hand, is a nitrogenous acid which, under the influence of hydro- 

 lytic agencies, splits up into amido-acetic acid (glycocoll) arid into a 

 non-nitrogenous acid, termed cholalic acid. Taurocholic acid, on 

 the other hand, contains not only nitrogen but sulphur and, under 

 hydrolytic agencies, splits up into amido-ethylsulphonic acid (taurine) 

 and into cholalic acid. The cholalic acid of the bile of certain 

 animals (as the pig and the goose) has a slightly different compo- 

 sition from that of the normal cholalic acid, and thus we may have 

 a glykocholic or a taurocholic acid not absolutely identical with those 



)f the ox. These observations will render intelligible the statement 



>reviously made that the bile of all animals contains a glykocholic 



>r a taurocholic acid or a mixture of the two. 



As will be afterwards stated in detail, the bile of herbivora 

 mtains glykocholic acid as its principal bile acid, whilst the bile of 

 trnivora contains taurocholic acid as its chief or sole bile acid. The 



)ile of man contains a preponderance of glykocholic acid, taurocholic 

 nd being sometimes absent. 

 The bile of nearly all classes of animals, with the exception of 



that of fishes, contains sodium salts of the bile acids. In salt water 



ishes, however, the bile acids are in combination with potassium ; in 

 fresh water fishes both potassium and sodium salts exist, the latter 



predominating. The same curious fact has been observed in the bile 

 of certain ' Chelonii! 



The Early History of researches on the Bile Adds. 

 The views of When we consider how important a part the older 

 Ta^ueUn **^ physicians ascribed to the bile in the causation of 

 disease we cannot be surprised to find that this secre- 

 tion was amongst the first to be subjected to investigation. Passing 

 -over, for the present, the observations made before chemistry had 

 attained to the position of a positive science, the first to be noticed 

 are those of Fourcroy and Vauquelin 2 , whose views do not appear 

 /to have differed materially from those which had prevailed concern- 



1 Plattner, Ann. d. Chem. u. Pharm., Vol. LI. (1844). 



2 Fourcroy, ' Systeme des connaissances chemiques.' Quoted by Berzelius in his 

 article 'Galle' in Wagner's Handworterbuch der Physiologic, Vol. I. (1842), p. 516. 

 .The Author has not been able to see the original. 



192 



