532 



THE UVEK 



[CH. XXXV. 



The constituents of the bile are the bile salts proper (tauro- 

 cholate and glycocholate of soda), the bile pigments (bilirubin, 

 biliverdin), a mucinoid substance, small quantities of fats, soaps, 

 cholesterin, lecithin, urea, and mineral salts, of which sodium 

 chloride and phosphates of calcium and iron are the most important. 



Bile is a yellowish, reddish-brown, or green fluid, according to the 

 relative preponderance of its two chief pigments. It has a musk-lik@ 

 odour, a bitter-sweet taste, and an alkaline reaction. 



The specific gravity of human bile from the gall-bladder is 1026 

 to 1032; that from a fistula, 1010 to 1011. The greater concentra- 

 tion of gall-bladder bile is partly explained by the addition to it 

 from the walls of that cavity of the mucinoid material it secretes. 



The amount of solids in gall-bladder bile is from 9 to 14 per 

 cent., in fistula bile from 1/5 to 3 per cent. The following table shows 

 that this low percentage of solids is almost entirely due to want of bile 

 salts. This can be accounted for in the way first suggested by Schiff 

 that there is normally a bile circulation going on in the body, a 

 large quantity of the bile salts that pass into the intestine being first 

 split up, then reabsorbed and again secreted. Such a circulation 

 would obviously be impossible in cases where all the bile is dis- 

 charged to the exterior. 



The following table gives some analyses of human bile : 



Bile Mucin. There has been considerable diversity of opinion 

 as to whether bile mucin is really mucin. The most recent work in 

 Hammarsten's laboratory shows that differences occur in different 

 animals. Thus in the ox there is very little true mucin, but a great 

 amount of nucleo-protein ; in human bile, on the other hand, there 

 is very little if any nucleo-protein; the mucinoid material present 

 there is really mucin. 



The Bile Salts. The bile contains the sodium salts of complex 



