DIGESTION. 55 



What conditions favor the action of the pancreatic fluid ? 



Moderate heat (100 F.), an alkaline medium, and the removal 

 of the products of the ferment-action as soon as the change is 

 completed. 



What name is given to the intestinal contents of the pancreatic 

 digestion ? 



Chyle. 



Describe the liver. 



The liver is the largest gland in the body, and is situated in the 

 upper part of the abdominal cavity. It secretes a fluid known as 

 the bile or gall, which is stored in a bladder lying attached to its 

 lower surface. The functions of the organ are (1) secretion, and 

 (2) the elaboration of the blood. 



What is the character of bile ? 



It is a viscid, almost ropy fluid, of a yellow or red or greenish 

 color and bitter taste. It is faintly alkaline or neutral in reaction, 

 and has a specific gravity of about 1020. Its composition is, 

 approximately 



Water 86 



C Bile salts, 9 ~) 



Organic matter, < Fat and cholesterin, 1 y .... 13 



( Mucus and pigments, 3 j 

 Inorganic salts 1 



100 

 How is the flow of bile excited ? 



The secretion of the liver is stored in the gall-bladder until its 

 flow is excited by the acid discharge of the stomach-contents into 

 the duodenum. It is an active secretion, and not a passive filtra- 

 tion from the blood, for if a manometer-tube be fastened in the 

 duct it will indicate a pressure greater than that of the blood. 

 While the gall-bladder acts as a storage reservoir, the bile does not 

 necessarily enter it, but may discharge directly from the hepatic 

 into the common duct. The opening of the common duct into the 

 duodenum is guarded by a sphincter-like arrangement of the muscu- 

 lar fibres in the gut-wall. The gall-bladder and the gall-duct are 

 provided with unstriped muscular fibres, so that they may empty 

 themselves. Inspiration and expiration bring alternating pressure 

 upon the gall-bladder, and aid in emptying it. 



