THE LIVEK. 163 



happens in a few fishes that these lobes are quite discon- 

 nected, forming symmetrically placed right and left livers. 

 Before birth the liver bears a much larger proportion to the 

 body than it does afterwards; and the bile which is at that 

 time secreted by it accumulates in the intestine, to be ex- 

 pelled when the child is born, and is called meconium. 

 Originally the liver occupies the whole of the upper part of 

 the abdomen, and the left lobe is as large as the right; but 

 this does not continue long; and in the adult, the left lobe is 

 comparatively small, and falls considerably short of reaching 

 the left side of the body. 



The greater part of the blood sent to the liver enters it by 

 the portal vein, and comes from 

 the stomach, intestine, and 

 spleen; but there is likewise a 

 hepatic artery which nourishes 

 the textures of the viscus; and 

 the blood entering by this 

 channel is afterwards conveyed 

 to the capillaries of the portal 

 system. The hepatic substance 

 is arranged in minute lobules,^ 

 each of which has ramifications . 

 of the portal vein in its circum- " 

 ference, and in its centre a 

 radicle of the hepatic vein, by Fig. 86. HEPATIC LOBULE, 

 which the blood is carried from capillary network : radicle of 

 ,i T , j-i A hepatic vein in the centre, 



the liver into the vena cava. A an g branclies of porta i vein 



rich network of small-meshed a t the circumference, together 

 capillaries not only unites the with two small twigs of hep- 

 branches of the portal and atic artery, 

 hepatic veins, but pervades the whole organ, passing con- 

 tinuously from one lobule to another. Only a few animals, 

 such as the pig, furnish an exception to this rule, and have 

 the hepatic lobules distinct. 



When the blood-vessels are empty, a section of liver under 

 the microscope exhibits little else than a mass of nucleated 

 corpuscles. These corpuscles, termed the hepatic cells, are 

 somewhat flattened polyhedral bodies of an average diameter 

 of T ^Q o- of an inch, of a yellowish tinge, containing numerous 



