The hepatic duct is formed by the union of a right and left branch, which issue from the bottom of the transverse fissure and unite at a very obtuse angle; it descends to the right, within the gastro-hepatic omentum. Its diameter is nearly two lines, and its length nearly two inches. At its lower end it meets the cystic descending from the gall bladder, and the ducts uniting together at an angle form the common bile duct. The cystic duct is about one and a half inches in length. The gall bladder is a pear-shaped membranous sac, three or four inches long, about an inch and a half across its widest part, and capable of containing from 8 to 12 fluid drachms. The gall bladder is attached to the liver. The neck, gradually narrowing, becoming constricted, bends downward, and terminates in the cystic duct. The common bile duct (ductus communis choledicus), the largest of the ducts, being from two to three lines in width, and nearly three inches long, conveys the bile from the liver and the gall bladder into the duodenum by a common orifice, with the pancreatic duct on its inner surface, about three to four inches below the pylorus. The liver is an extremely vascular organ, and receives its blood supply from two distinct vessels, the portal vein and the hepatic artery, while the blood is returned from it into the inferior vena cava by the hepatic vein. Its secretion, the bile, is conveyed from it by the hepatic duct, either directly into the intestines, or, when digestion is not going on, into the cystic duct, and thence into the gall bladder, where it accumulates until required. The portal vein, hepatic artery, and hepatic duct branch together throughout the liver, while the hepatic vein and its tributaries run by themselves. At the transverse fissure it is merged into the areolar investment called Glisson's capsule, which surrounds the portal vein, hepatic artery, and hepatic duct, as they enter at this part, and accompanies them in their branches through the substance of the liver. The liver is made up of small roundish or oval portions called lobules, each of which is about 1/20 of an inch in diameter, and composed of minute branches of the portal vein, hepatic artery, hepatic duct, and hepatic vein; while the interstices of these vessels are filled by liver cells. These cells, which make up a great portion of the substance of the organ, are of rounded or polygonal form; about 1/800 to 1/1000 of an inch in diameter. The function of the liver is the secretion of bile. The bile is a somewhat viscid fluid of a yellow, or greenish-yellow, color, a strongly bitter taste, and when fresh a scarcely perceptible odor. It has a neutral or slightly alkaline reaction, and its specific gravity is 1.020. The composition of human bile is: Water, 859.2 Solids, 140.8 ------- 1,000 The solids are: