THE LIVER, 183 



for absorption by the lacteals which communicate with the intes- 

 tines. It is now termed chyle, and is a white milky fluid which 

 enters the thoracic duct and mingles with the blood as previously 

 described. The refuse and insoluble portion of the food, with un- 

 used portions of the bile pass on through the lower intestines, and 

 is discharged by the rectum as dung. 



The liver is a large organ with the appearance of which almost 

 every person is familiar. It is called a gland, because its office is 

 to secrete a fluid which is peculiar to it, and it is the largest gland 

 in the body. Its secretion is called the bile. Its position in the 

 body is below the diaphragm and adjacent to the stomachs, with 

 the third of which it is in direct contact. It is enveloped in the 

 peritoneum or membrane which covers and also encloses the whole 

 of the contents of the abdomen, and forms as it were a sac or bag, 

 one-half of which is doubled into the other half. The liver in sub- 

 stance is granular, consisting of grains, or lobules, from one-tenth 

 to one-twentieth of an inch in diameter. Its color is reddish 

 brown. The lobules of which it is composed are closely packed, 

 and are held together by fine tissue and a net-work of minute 

 veins and ducts. Each lobule is connected with a blood vessel at 

 its base, and another vessel comes from the center of the lobule 

 and joins the former one at its base. Between these two is an 

 exceedingly fine net-work of capillary vessels similar to those pre- 

 viously described. By means of arteries and veins called portal 

 canals, which enter and ramify through the substance of the liver, 

 the blood is carried into and through the substance of each lobule 

 in streams of exceeding fineness. From the blood thus passing 

 through the lobules, the gall or bile is secreted by small cells not ex- 

 ceeding Yioooth of an inch in diameter, and is collected into minute 

 vessels called biliary ducts, from which it is gathered into larger 

 ducts, which pour their contents into the great bile ducts. There is 

 a receptacle in the liver of the sheep known as the gall-bladder, to 

 Which the gall is carried from the hepatic duct by another duct 

 named the cystic duct. When the gall contained in the gall-blad- 

 der is required for use, it returns by the same duct into the hepatic 

 duct, and thence into the great bile duct which ends in the duo- 

 denum, below the stomach. 



The gall is an alkaline fluid of composite character, containing 

 soda, two peculiar acids, (glycocholic and taurocholic, the latter of 

 which contains sulphur) ; mucus ; cholesterine ; stearic, oleic, and 

 lactic acids, with potash and ammonia, and a peculiar coloring 

 matter. It is in fact a sort of liquid soap. The bile is poured 

 ipto the duodenum by the great bile duct. Near this duct is 



