This section is from the book "Fletcherism. What It Is, Or How I Became Young At Sixty", by Horace Fletcher. Also available from Amazon: Fletcherism, What It Is, Or How I Became Young At Sixty.
Hold the face down, so that the tongue hangs perpendicularly in the mouth. This is for two reasons: one, because it will show how food, when properly mixed with saliva, will be lifted up in the hollow part in the middle of the tongue, against the direct force of gravity, and will collect at the place where the mouth is shut off at the back, the food-gate.
It is a real gate; and while the food is being masticated, so that it may be mixed with saliva and chemically transformed from its crude condition into the chemical form that makes it possible of digestion and absorption, this gate will remain tightly shut, and the throat will be entirely cut off from the mouth.
But as the food becomes creamy, so to speak, through being mixed with saliva, or emulsified, or alkalised, or neutralised, or dextrinised, or modified in whatever form Nature requires, the creamy substance will be drawn up the central conduit of the tongue until it reaches the food-gate.
If it is found by the taste-buds there located around the "circumvalate papillae" (the teat-like projections on the tongue which I mentioned above) to be properly prepared for acceptance and further digestion, the food-gate will open, and the food thus ready for acceptance into the body will be sucked back and swallowed unconsciously - that is, without conscious effort.
I now started to experiment on myself. I chewed my food carefully until I extracted all taste from it there was in it, and until it slipped unconsciously down my throat. When the appetite ceased, and I was thereby told that I had had enough, I stopped; and I had no desire to eat any more until a real appetite commanded me again. Then I again chewed carefully - eating always whatever the appetite craved.