36 HUMAN PHYSIOLOGY. 



The total quantity of this fluid secreted in twenty-four hours has not 

 been accurately determined ; it varies from one to two pounds ; it is poured 

 out most abundantly an hour after meals. 



The Bile has an important influence in the elaboration of the food and 

 its preparation for absorption. It is a golden-brown, viscid fluid, having a 

 neutral or alkaline reaction and a specific gravity of 1.020. 



COMPOSITION OF BILE. 



Water, 859.2 



Sodium glycocholate, ^ 



Sodium taurocholate, j 9 I -4 



Fat, 9.2 



Cholesterine, 2.6 



Mucus and coloring matter, 29.8 



Salts, 7.8 



1000.00 



The Biliary salts, sodium glycocholate and taurocholate, are character- 

 istic ingredients, and are formed in the liver by the process of secretion, 

 from materials furnished by the blood. It is probable that they are derived 

 from the nitrogenized compounds, though the stages in the process are 

 unknown. They are reabsorbed from the small intestine to play some 

 ulterior part in nutrition. 



Cholesterine is a product of waste taken up by the blood from the nervous 

 tissues and excreted by the liver. It crystallizes in the form of rhombic 

 plates, which are quite transparent. When retained within the blood, it 

 gives rise to the condition of cholesterczmia, attended with severe nervous 

 symptoms. It is given off in the feces under the form of stercorine. 



The Coloring matters which give the tints to the bile are biliverdin and 

 bilirubin y and are probably derived from the coloring matter of the blood. 

 Their presence in any fluid can be recognized by adding to it nitric acid 

 containing nitrous acid, when a play of colors is observed, beginning with 

 green, blue, violet, red and yellow. 



The Bile is both a secretion and an excretion ; it is constantly being 

 formed and discharged by the hepatic ducts into the gall bladder, in which 

 it is stored up, during the intervals of digestion. As soon as food enters 

 the intestines, it is poured out abundantly, by the contraction of the walls 

 of the gall bladder. 



The Amount secreted in 24 hours is about 2^ pounds. 



Functions of the Bile, (i) It assists in the emulsifi cation of the fats 

 and promotes their absorption. (2) It tends to prevent putrefactive changes 



