Because, after the teeth, the tongue, and the muscles of the mouth generally, have rolled the food into a soft bolus, it is conveyed to the back of the mouth, where it is set upon the opening of the throat (œsophagus). It does not then descend through the throat by its own gravity, because the throat is generally in a compressed or collapsed state, like an empty tube; and we know that persons can eat or drink when with their heads downwards. The œsophagus is formed of a number of muscular threads, or rings, and each little thread is like a hand ready to grasp at the morsel that is coming. As soon as the bolus is presented at the top of the throat, these little muscular hands lay hold of it, and transmit it downward, passing it from one to another, until it is conveyed through the long passage, to the door of the stomach, which it enters.
"Remove far from me poverty and lies; give me neither poverty nor riches; feed me with food convenient for me."—Proverbs xxx.
Fig. 49.—SECTION OF THE STOMACH, &c.
A. The inner coat of the stomach. (The stomach is here represented cut through its length, so that we can see its inside.)
B. The lower extremity of the throat, or œsophagus, through which food enters the stomach.