Section 30. the Walls of the Whole of the Small Intestine Are Engaged

in the absorption of the soluble results of digestion. In the duodenum, especially, small processes, the villi project into the cavity, and being, like the small hairs of velvet pile, and as thickly set, give its inner coat a velvety appearance. In a villus we find (Figure IX., Sheet 3) a series of small blood-vessels and with it another vessel called a lacteal. The lacteals run together into larger and larger branches until they form a main trunk, the thoracic duct, which opens into the blood circulation at a point near the heart; but of this we shall speak further later. They contain, after a meal, a fluid called chyle.