BILE. 



The function of the bile is mainly excretory in character, 

 consisting in the removal by way of the intestine of various 

 relatively insoluble substances, such as cholesterol and leci- 

 thin. Secondarily, it exerts an emulsifying power upon 

 the fats, and fat absorption is markedly decreased in its 

 absence. In this sense it may be classed under the digestive 

 juices. 



Bile as it is secreted by the liver forms a clear, limpid 

 solution of a color either yellowish-red, brown, or green ac- 

 cording to the species of animal from which it is obtained. 

 It reacts alkaline to litmus, but acid to phenolphthalein and 

 possesses a decidedly bitter taste and an odor of musk. By 

 its stay in the gall-bladder the character of the fluid is 

 changed considerably. Absorption of water and admix- 

 ture of mucus-like substances derived from the walls of the 

 bladder increase the specific gravity from 1.010 to 1.035. 

 When taken from the gall-bladder, bile, therefore, presents 

 a ropy, viscous appearance and contains about 10 per cent 

 of solids. Bile holds the following substances in solution: 

 the salts of the bile-acids, the bile-pigments, mucin or phospho- 

 protein, cholesterol, lecithin, inorganic salts, and traces of 

 fat, soaps, and urea. 



Note the color, consistency, and reaction of the samples 

 presented. 



Notice the differences in color between the ox and dog 



bile. 



67 



