The Intestines. When the food has been sufficiently melted and partially digested in the stomach, it is pushed on into a long tube called the _intestine_, or _bowel_. During its passage through this part of the food tube, it is taken up into the veins, and carried to the heart. From here it is pumped all over the body to feed and nourish the millions of little cells of which the body is built. This bowel tube, or intestine, which, on account of its length, is arranged in coils, finally delivers the undigested remains of the food into a somewhat larger tube called the _large intestine_, in the lower and back part of the body, where its remaining moisture is sucked out of it, and its solid waste material passed out of the body through the _rectum_ in the form of the _feces_. THE JOURNEY DOWN THE FOOD TUBE The Flow of Saliva and "Appetite Juice." We are now ready to start some food-fuel, say a piece of bread, on its journey down our food tube, or _alimentary canal_. One would naturally suppose that the process of digestion would not begin until the food got well between our teeth; but, as a matter of fact, it begins before it enters our lips, or even before it leaves the table. If bread be toasted or freshly baked, the mere smell of it will start our mouths to watering; nay, even the mere sight of food, as in a pastry cook's window, with the glass between us and it, will start up this preparation for the feast. This flow of saliva in the mouth is of great assistance in moistening the bread while we are chewing it; but it goes farther than this. Some of the saliva is swallowed before we begin to eat; and this goes down into the stomach and brings word to the juices there to be ready, for something is coming. As the food approaches the mouth, a message also is telegraphed down the nerves to the stomach, which at once actively sets to work pouring out a digestive juice in readiness, called the "appetite juice." This shows how important are, not merely a good appetite, but also attractive appearance and flavor in our food; for if this appetite juice is not secreted, the food may lie in the stomach for hours before the proper process of digestion, or melting, begins. The Salivary Glands. Now, where does this saliva in the mouth come from? It is poured out from the pouches of the cheeks, and from under the tongue, by some little living sponges, or juice factories, known as _salivary glands_.[2] [Illustration: THE SALIVARY GLANDS In this diagram are shown the three glands (_G_) of the left side. The duct (_D_) from the parotid gland empties through the lining of the cheek; those from the lower glands empty at the front of the mouth under the tongue (_T_). _N_, nerve; _A_, artery; _V_, vein.]