878. Why do we feel drowsy after eating heartily?
Because, while the stomach is in action, a great proportion of the blood of the body is drawn towards it, and as the blood is withdrawn from the other parts of the body, they fall into a state of languor.
879. Why does blood flow more freely to the stomach during digestion?
Because the energy of an organ is increased by the flow of blood, which supplies the material of which our organs are composed, and in which the vital essence, supporting life, resides.
880. Why does excess in eating bring on indigestion?
Because the power of the stomach to digest food is governed by the amount of food required by the system. It seems to be an instinct of the stomach to hold back food which is in excess, and by indications of pain and disturbance to warn its master that excess has been committed.
881. Why is food digested in the stomach?
Because it enters the stomach in the form of a paste, produced by the action of the mouth; and directly food enters, the gastric juice, which is formed by glands embedded in the coats of the stomach, trickles down its sides. This is a more powerful solvent than the salivary juice—it is like the same kind of fluid, only much stronger, and it soon turns the food from a rough and crude paste into a greyish cream (chyme). The heat of the stomach assists the operation, and the muscular threads of the coats move the cream along, in the same manner that the muscles of the œsophagus brought down the food.
The cream is passed towards the door which leads outward from the stomach (pylorus); but if, in the midst of the cream, there are any undissolved particles of food, it closes upon them, and they return again to the stomach to be further changed.