About the level of the orifice of the pancreatic duct in the duodenum is found another small opening, which is that of the bile duct. Through this the bile is poured into the intestine. The bile is produced in the liver. The liver is the largest, the most complex, and one of the most important organs of the body. It is lodged in the right side, and fills up a large cavity which is hollowed for it in the base of the right lung, and bounded by the lower edge of the ribs. The liver is composed of large, irregularly shaped, flattened cells, which are closely covered by an exceedingly fine network of blood vessels. One set of these blood vessels is derived from the portal vein, and the blood passing through them contains, as we shall see when considering the question of absorption, a large amount of the products of digestion. The minute final radicles of these blood vessels communicate with another set of radicles, which after ramifying on the surface of the liver cells, collect into larger branches, and finally form the hepatic vein. The hepatic vein pours its contents into the vena cava or large blood vessel which conducts the blood to the right side of the heart. From this short description it will be seen that the products of digestion are brought into close relation with the liver cells. The bile arises originally in the interstices between the liver cells, and in what are at first wall-less canals; these minute ducts contain an acrid greenish-brown substance, known as the bile. The ducts gradually grow in size as they run together, and they finally pour their contents into a strong muscular tube by which they are conveyed to a hollow sack-like body called the gall bladder. In the gall bladder the bile is stored for future use. At the moment that the food passes into the duodenum the bile is slowly poured out from the bile duct into the duodenum. This discharge of bile continues during the whole process of digestion.