BRAIN, n. An apparatus with which we think what we think. That which distinguishes the man who is content to be something from the man who wishes to do something. A man of great wealth, or one who has been pitchforked into high station, has commonly such a headful of brain that his neighbors cannot keep their hats on. In our civilization, and under our republican form of government, brain is so highly honored that it is rewarded by exemption from the cares of office.
2009 Update: An organ ingeniously, though mindlessly, devised by nature to absorb the force of impact against the cranium from, for example, walls, trees or incited violence. Nature's styrofoam peanut.
Without a soft, spongy, compressible brain to fill the interior, injuries such as the one depicted (right) would pose a much greater threat to the integrity of the skull.
Happy birthday, to my brother, Andy. (Be assured, today's word selection is purely coincidental)
Happy birthday, also, to Nessa.