LIVER. 315 



into the several openings in the posterior or transverse fissure ; 

 numerous plates from it penetrate the substance of the gland, 

 and separate the ultimate hepatic lobules. This inflected sheath 

 is named Glisson's capsule, and processes from it line the portal 

 canals, which pierce the substance of the liver, and envelop the 

 branches of the portal vein, the hepatic artery, and biliary ducts, 

 which run in these canals. It thus forms a web in which these 

 vessels ramify, and surrounds the lobules, binding them together. 

 It is divided into two portions ; the vaginal, loose and abundant, 

 lining the portal canals ; and the interlobular, which forms the 

 capsules of the lobules, and supports the ramifications of the 

 smaller vessels. 



The hepatic substance is variable in colour, depending upon 

 the quantity and quality of the blood and bile in its vessels. Its 

 normal colour is a cool brown ; in an animal that has died from 

 haemorrhage it is a bleached yellowish grey ; from general con- 

 gestion, a purplish-brown or chocolate ; from obstruction of the 

 biliary ducts, yellow. It is easily lacerated, the rupture being 

 granulated. It consists of very minute lobules, varying from about 

 jJ^ to -jJg- of an inch in diameter, separated from each other 

 by the interlobular tissue, continuous with Glisson's capsule. 

 A lobule is divided externally into a base, and capsular surface 

 or periphery. The base is polygonal and flat, resting upon a. 

 small branch of the hepatic vein — the sublobular ; joining which, 

 and piercing the centre of the lobule, is the intralobular vein. 

 The periphery or capsular surface is developed into blunt pro- 

 cesses, giving the lobule, which cut longitudinally, a foliated 

 appearance. The surfaces are imperfectly isolated from the 

 surrounding lobules by a thin layer 6f Glisson's capsule and by 

 the smaller vessels, the intervals being the interlobular spaces. 

 Each lobule consists of numerous cells, biliary ductlets, a plexus of 

 capillary blood-vessels, and probably minute nerves and absorbents. 

 Hepatic cells form the bulk of each lobule, and are irregularly 

 polygonal in shape, averaging about -^^ of an inch in diameter, 

 and containing a nucleus, nucleolus, granular matter, and particles 

 of fat. They are arranged in rows, radiating from the centre of 

 the lobule, and lie in the interspaces of the vascular plexuses. 



The liver is supplied with nutritive blood by the hepatic artery, 

 a branch of the coeliac axis ; with functional blood by the portal 

 vein, both kinds of blood being returned by the hepatic veins. 



The portal vein enters the liver at the transverse fissure. 



