“You are old, Father William,” the young man said, “and your hair has become very white; and yet you incessantly stand on your head – do you think, at your age, it is right?”

In my youth,” Father William replied to his son, “I feared it might injure the brain; but now that I’m perfectly sure I have none, why, I do it again and again.”

Alice’s Adventures in Wonderland by Lewis Carroll (1865)