240 HEALTH AND DISEASE 



and, as an exception to the usual behaviour of veins, instead of joining a 

 larger vein, which in this case would be the vena cava, it proceeds to break 

 up as if it were an artery, into smaller and still smaller branches, which run 

 between the lobules and are hence called interlobular veins (3, 3, fig. 90). 

 From these, minute branches are given off which enter the lobules and there 

 form a net- work of capillary vessels ramifying among the cells (2, 2, fig. 90), 

 and then, after uniting and reuniting, form a blood-vessel which runs down 

 the centre of the lobule and is known as the intralobular vein (1, fig. 90). 

 From this the blood passes out of the lobules into a set of veins beneath 

 it (sublobular veins), and then enters the hepatic vein. The blood as it 



i. — Section of Lobule of H 



1 Hepatic cell. - Nucleus. * Section of intralobular or central vein. 2 Its smaller 



3 Granules of fat, pigment, and tributaries, which receive the blood from 3 and convey it to 1. 



glycogen. 4 Bile capillaries. 3 Interlobular or peripheric branches of the vena porta. 



traverses this close net- work of capillaries within the lobules comes into inti- 

 mate relations with the gland cells which occupy the spaces between them. 



The bile-ducts commence in the form of an extremely delicate net- 

 work of tubes which ramify over and between the gland cells in the 

 lobule, and take up from them the bile they have secreted. After uniting 

 to form larger and larger tubes they at length terminate in the common 

 bile-duct. This opens into the first part of the intestine just beyond the 

 stomach in common with the duct of the pancreas. No gall-bladder is 

 present in the horse. 



The bile is a glairy fluid of yellow, green, or olive-brown colour, 

 alkaline reaction, nauseous smell, and bitter taste. It has a specific gravity 

 of about T030. It has been estimated that a horse secretes about -^ part 

 of its weight of bile in twenty-four hours, or about 12 or 14 lbs. The 

 flow of bile into the intestine increases about an hour after food has been 

 ingested, and the quantity continues to be large for some hours, when it 

 gradually declines till after the next meal. 



