442 PHYSIOLOGY AND MORPHOLOGY OF ANIMALS. 



two. Besides these tubes, of course, there are the bile 

 ducts (Fig. 306) ; but these, like all excretory tubes, end 

 in blind extremities (Fig. 305). As we shall see pres- 

 ently, the products of the liver are bile and sugar. Of 

 these, the bile is carried away by the biliary ducts into 



Fig. 306. — Diagram showing the distribution of the blood through the liver. 

 The arrows show the direction of the current. 



the intestines, while the sugar is delivered to the blood 

 and carried into the general circulation by the hepatic 

 vein. 



2. Function : Two General Kinds of Glands.— 



Glands are of two general kinds — ducted and ductless. 

 The one delivers its products by a duct to the surface, 

 the other delivers its product directly to the blood with- 

 out a duct. We have already seen two examples of 

 these in the lymphatic glands and the spleen, and have 

 stated (page 324) that the pancreas is also partly so. 



