Answer:
What goes around and around the wood, but never goes into the wood?
It holds most knowledge that has ever been said. But is not the brain, is not the head. To feathers and their masters, it's both bane and boonΒ One empty, and one full.
They can be harbored, but few hold water. You can nurse them, but only by holding them against someone else. You can carry them, but not with your arms. You can bury them, but not in the earth.
The more of them you take, the more you leave behind. What are they?
Round as a button, deep as a well. If you want me to talk, you must first pull my tail.
The sun bakes them, The hand breaks them, The foot treads on them, And the mouth tastes them. What are they?