DIGESTION. 



273 



The gall-bladder and all the main biliary ducts are provided with 

 mucous glands, which open on their internal surface. 



Functions of the Liver. The functions of the Liver may be 

 classified under the following heads: 1. The Secretion of Bile. 2. The 

 Elaboration of Blood; under this head may be included the Glycogenic 

 Function. 



I. THE SECRETION OF BILE. 



Properties of the Bile. The bile is a somewhat viscid fluid, of a 

 yellow or reddish-yellow color, a strongly bitter taste, and, when fresh, 

 with a scarcely perceptible odor: it has a neutral or slightly alkaline reac- 

 tion, and its specific gravity is about 1020. Its color and degree of con- 

 sistence vary much, apparently independent of disease; but? as a rule, it 

 becomes gradually more deeply colored and thicker as it advances along 

 its ducts, or when it remains long in the gall-bladder, wherein, at the 

 same time, it becomes more viscid and ropy, of a darker color, and more 

 bitter taste, mainly from its greater degree of concentration, on account 

 of partial absorption of its water, but partly also from being mixed with 

 mucus. 



Chemical Composition of Human Bile. (Frerichs.) 



Water 

 Solids 



Bile salts or Bilin . 



Fat .... 



Cholesterin 



Mucus and coloring matters 



Salts 



859-2 

 140-8 



1000-0 



91-5 

 9-2 

 2.6 



29.8 



7-7 



140-8 



Bile salts, or Bilin, can be obtained as colorless, exceedingly deliques- 

 cent crystals, soluble in water, alcohol, and alkaline solutions, giving to- 

 the watery solution the taste and general characters of bile. They consist 

 of sodium salts of glycocholic and taurocholic acids. The former salt is 

 composed of cholic acid conjugated with glycin (see Appendix), the latter 

 of the same acid conjugated with taurin. The proportion of these two- 

 salts in the bile of different animals varies, e.g., in ox bile the glycocho- 

 late is in great excess, whereas the bile of the dog, cat, bear, and other 

 carnivora contains taurocholate alone; in human bile both are present in 

 about the same amount (glycocholate in excess?). 



Preparation of Bile Salt. Bile salts may be prepared in the fol- 

 VOL. I. 18. 



