HOW DOES ANYBODY KNOW THIS?
A soldier was once shot in the side in such a way that when the wound healed, it left an opening with a piece of loose skin over it, like a little door leading into his stomach.
A doctor who wished to learn about the stomach, hired him for a servant and used to study him every day.
He would push aside the little flap of skin and put into the stomach any kind of food that he pleased, and then watch to see what happened to it.
In this way, he learned a great deal and wrote it down, so that other people might know, too. In other ways, also, which it would take too long to tell you here, doctors have learned how these magical food-bags take care of our food.
WHY DOES THE FOOD NEED TO BE CHANGED?
Your mamma tells you sometimes at breakfast that you must eat oat-meal and milk to make you grow into a big man or woman.
Did you ever wonder what part of you is made of oat-meal, or what part of milk?
That stout little arm does not look like oat-meal; those rosy cheeks do not look like milk.
If our food is to make stout arms and rosy cheeks, strong bodies and busy brains, it must first be changed into a form in which it can get to each part and feed it.