THE LIVER. 585 



ward to the left, where it becomes somewhat convoluted, 

 and ends in a tube, called the cystic duct, about an inch 

 and a half long, which has already been described as join- 

 ing the hepatic, to form the ductus communis choledochus , 

 whose entrance into the duodenum has already been traced. 



The gall-bladder has three coats. The first, or perito- 

 neal, is partial, covering only the anterior surface; the 

 second consists of condensed cellular structure, and is called 

 the fibrous ; while the third, which is internal, is the mu- 

 cous coat. This coat presents wrinkles or folds which take 

 a tortuous or spiral course, and have between them nu- 

 merous cells, which give the surface of this coat a honey- 

 comb appearance. This coat is always found colored, either 

 yellow or green, from the bile. 



Blood-vessels. The artery of the gall-bladder, the cystic, 

 comes from the hepatic. Its vein goes to the vena portae. 

 Its nerves come from the sympathetic. Its lymphatics 

 are numerous, and unite with those of the liver. The gall- 

 bladder is developed by an offset from the hepatic duct. 



function of the Liver. The office of this viscus is clearly 

 to secrete the bile, which secretion is found to occur in the 

 lobules or acini, from the blood of the portal vein. 



The bile is a viscid fluid, of a yellow or greenish yellow 

 color, and a very bitter taste. It is said to consist of chole- 

 sterine, which is a white, fatty, crystallizable substance, re- 

 sembling spermaceti; choleic acid, which is a peculiar 

 animal substance combined with soda ; and coloring matter 

 called biliverdin. The chemical analysis of Berzelius makes 

 bile to consist of water, 80 parts ; bilin, a substance taking 

 the resinous condition by the application of an acid, 8 parts ; 

 mucus, 3 parts ; saline substances, of which soda is the 

 prominent, 9 parts. 



The offices of the bile are, first, to act upon the chyme in 

 the duodenum, in. its conversion into chyle; second, a por- 

 tion of it unites with the residuum of the chyle, and is passed 

 off by the bowels as excrement, thus ridding the blood of 

 its superfluous hydro-carbon ; third, it excites the peri- 

 staltic action of the muscular coat, and acts as a stimulus to 



