DIGESTION IN THE SMALL INTESTINE. 383 



the liver through the portal vein, indicating the functional relation of 

 the liver to the process of intestinal digestion. 



1. The chemical characteristics of the bile have been mostly studied 

 in the fluids found in the gall-bladder of the ox and in that obtained 

 from fistulae in dogs. In the fresh state, bile is a clear, thin, or more or 

 less tenacious liquid, which, with the exception of epithelial cells from 

 the gall-bladder, contains no morphological elements. It has. a neutral 

 or alkaline reaction. When fresh, in man and carnivora, it is of a golden 

 3 T ellow or greenish-brown color ; it is green in herbivora (brownish-green 

 in the horse and ox, greenish-yellow in the hog, and dark green in 

 sheep). After standing exposed to the air, the brownish-yellow bile 

 becomes dark brown, and the greenish bile more intensified to a dark 

 green. Bile has a peculiar bitter taste, and when warmed a musk-like 

 odor. The specific gravity varies in different animals from 1008 to 1030, 

 the highest being found in bile taken from the gall-bladder of man. 

 Ox-bile is often yellowish-brown, though usually green in color, and 

 may be either clear or turbid ; it is alkaline, viscid, and contains a 

 large amount of mucin ; its specific gravity varies from 1022 to 1025. 

 Sheep's bile is usually green, is odorless, clear, alkaline, and, although it 

 contains mucin, is not viscid; specific gravity, 1025 to 1031. Calves' 

 bile is green or yellowish-brown, though sometimes golden yellow in thin 

 la}*ers ; it is clear, odorless, viscid, neutral in reaction, and contains but 

 little mucin; specific gravitj 7 , 1020 to 1027. Pig's bile is clear or dark 

 yellowish-brown or golden yellow (the latter when diluted), is odorless, 

 alkaline, contains large amounts of mucin, and is therefore very viscid ; 

 specific gravity, 1020 to 1027. Dog's bile is usually yellowish-brown, 

 and when diluted golden yellow ; it may be either neutral or alkaline, 

 contains mucin, and is clear and odorless; specific gravity, 1025. The 

 bile of all animals may be kept for several days, even at a high tempera- 

 ture, before putrefaction sets in. In the fresh secretion from the liver, 

 the solids in the bile of the cat, dog, and sheep amount to 5 per cent., in 

 the rabbit 2 per cent., and in the sheep 1-J- per cent. In the gall-bladder 

 in cats, dogs, and rabbits the solids rise from 2 to 20 per cent., in the 

 sheep to 8 per cent., in man from 9 to 17 per cent., and in the ox from 

 7 to 11 per cent.: the solids in the bile of man, the pig, and the ox consist 

 of only 1.5 per cent, of inorganic matter, and in the dog only 3.6 per cent. 



Doer. 



In 100 parts Bile. Man. Ox. Pig. , , 



Fresh. From Bladder. 

 Water, . 86.3 90.4 88.8 95.3 85.2 



Solids, 



Bile salts, 



Lecithin, cholesterin 



Fats, soaps, 



Mucin and coloring matter, 



.Inorganic salts, 



13.7 9.6 11.2 4.7 14.8 



7.4) 7.3 3.4 12.6 



> 8.0 



3.0) 2.2 0.5 1.3 



2.2 0.3 0.6 0.2 0.3 



1.1 1.3 1.1 0.6 0.6 



