MECHANISM OF BILE SECRETION. 

 By D. NOEL PATON. 



CONTENTS. Mode of Formation of Bile Constituents, p. 559 Water, p. 559 

 Inorganic Salts, p. 560 Nucleo-Proteid, p. 561 Bile Acids, p. 562 Bile Pig- 

 ments, p. 563 Cholesteriu, p. 564 Lecithin, etc., p. 564 Influence of various 

 Factors on the Secretion of Bile, p. 564 Flow of Blood, p. 565 Food, p. 565 

 Pressure of other Organs, p. 567 Nerves, p. 567 Chemical Substances, p. 

 567 General Conclusions, p. 569. 



IN considering the mechanism of bile secretion, it must be remembered 

 that the formation of bile is only one of many functions performed by 

 the liver. 



Placed as it is upon the course of the portal vein, the great channel 

 of absorption of material from the alimentary canal, the liver regulates 

 the supply of carbohydrates to the body by storing the surplus sugar 

 absorbed in the form of glycogen. It also gets rid of any excess of 

 nitrogen absorbed, by converting it into the innocuous and easily 

 eliminated urea. In addition to performing these functions, the liver 

 acts as one of the great storehouses of iron in the body, and in many 

 animals it is also a situation in which surplus fats are accumulated. 



When these numerous functions are considered, the small amount of 

 bile formed per diem by so large an organ is the less surprising. In man 

 about 800 or 900 grms. of bile, with about 14 or 15 grms. of solids, are 

 daily secreted from the liver, an organ which weighs about 1600 grms. 



In studying how bile is formed in the liver, it is necessary to 

 remember that, besides the great mass of liver cells, there are in- 

 numerable bile passages lined by a living epithelium. In most animals 

 a saccular diverticulum, the gall bladder, is developed upon these 

 passages. In this and in the passages the surplus bile accumulates. 

 How far the liver cells, and how far the cells lining the ducts, act in 

 producing the various constituents of bile, must be subsequently con- 

 sidered. 



The bile is a fluid containing many different substances in solution 

 (see article, " Chemistry of Bile " ), arid an investigation of the mechanism 

 of bile secretion necessitates a consideration of the mode of production 

 of each of these. 



MODE OF FORMATION OF BILE CONSTITUENTS. 



Water. The water of the bile is in part secreted from the walls 

 of the bile passages, for it has been found that when the cystic duct 

 is occluded, and the fundus of the gall bladder opened, a small amount 



