Assimilation.--Is the process whereby the digested food is carried into the blood stream, and thus conveyed to the different parts of the body where the hungry cells are in need of it. [Illustration: Fig. 1.--A bit of the inner coat of the small intestine.] Fine threads of blood vessels (capillaries) take it up from the stomach and intestines. Also along the intestines there are little projections (villi), through which the food passes into a blood stream leading to the liver, where the blood is then purified. These projections also contain lacteals or little vessels containing blood without its red corpuscles. A duct carries this colourless blood mixed with absorbed food to the left side of the neck, where it empties into the blood stream. These lacteals have a special affinity for the fat of the food. Most of the rest of the food, including the proteid and the carbohydrate or starchy portion now in the form of sugar, passes into the capillaries, and then is led to the liver. The liver will not let through more sugar than is required, storing it up for future use. It also acts as a careful guardian, by arresting many poisons which would otherwise pass into the general circulation. The liver requires for the proper performance of its functions plenty of pure blood, hence the necessity for fresh air and exercise, that the lungs may work well. The liver is easily influenced by alcoholic beverages, and by getting too hard work to do through eating rich foods. A consideration of this delicate and intricate process, whereby the digested food is absorbed, will show that badly-digested food can not hope to be well assimilated, consequently attention should be paid to the quantity and quality of the food we eat (_see_ Digestion; Diet). [Illustration: Fig. 2.--Two villi containing lacteals. The white canals are lacteals, the darker lines indicate blood vessels (capillaries). Magnified 100 diameters. (_From "Quain's Anatomy_.")]