~15.~ The liver is a very wonderful organ, and does many useful things besides making bile. It aids in various ways in digesting the food, and helps to keep the blood pure by removing from it harmful substances which are formed within the body. ~16. The Pancreas~(pan'-cre-as).--The _pancreas_ is another large and very important gland which is found close to the stomach, lying just behind it in the abdominal cavity. The pancreas forms a fluid called the _pancreatic juice_, which enters the small intestine at nearly the same place as the bile. ~17. The Spleen.~--Close to the pancreas, at the left side of the body, is a dark, roundish organ about the size of the fist, called the _spleen_. It is not known that the spleen has much to do in the work of digestion, but it is so closely connected with the digestive organs that we need to know about it. ~18.~ Please note that there are five important organs of digestion. The mouth, the stomach, the intestines, the pancreas, and the liver. ~19.~ Also observe that there are five digestive fluids, saliva, gastric juice, bile, pancreatic juice, and intestinal juice. SUMMARY. 1. The process of dissolving and changing the food so that it may be absorbed and may nourish the body is digestion. 2. The work of digestion is chiefly done in the digestive tube or canal, which is about thirty feet in length. 3. The mouth contains the teeth, and has three pairs of salivary glands connected with it, which make saliva. 4. The gullet leads from the mouth to the stomach. 5. The stomach is pear-shaped, and holds about three pints. 6. It has an upper and a lower opening, each of which is guarded by a muscle, which keeps its contents from escaping. 7. The lower opening of the stomach is called the pylorus. 8. The stomach forms the gastric juice. 9. The intestines are about twenty-five feet long. They form the intestinal juice. 10. The liver lies under the ribs of the right side. It is about half as large as the head. It makes bile. 11. When not needed for immediate use, the bile is stored up in a sac called the gall-bladder. 12. The pancreas is a gland which lies just back of the stomach. It makes pancreatic juice. 13. The spleen is found near the pancreas. 14. There are five important digestive organs--the mouth, the stomach, the intestines, the liver, and the pancreas. 15. There are five digestive fluids--saliva, gastric juice, intestinal juice, bile, and pancreatic juice. CHAPTER VIII. DIGESTION OF A MOUTHFUL OF BREAD. ~1.~ Let us suppose that we have eaten a mouthful of bread, and can watch it as it goes through all the different processes of digestion. ~2. Mastication.~--First, we chew or masticate the food with the teeth. We use the tongue to move the food from one side of the mouth to the other, and to keep the food between the teeth.