Today, when you tell someone to "get his or her head examined," you are usually implying that they are crazy. But the phrase had real currency in the 19th century. People really did get their heads examined--but not to find out they were crazy.
The phrase actually comes from the antebellum phrenology fad when people--all kinds of people, from president James Garfield to Walt Whitman--got their heads "read."Phrenologists could read your character, including what you are good at and what weren't, by looking at the bumps on your head. Supposedly, Clara Barton, founder of the Red Cross, and Ulysses S. Grant even picked their careers based on a head reading. Forget What Color is Your Parachute? In the 19th century, it was What Bumps are on My Brain?
Phrenology offered physical "proof" of your internal self. That was part of its appeal in an age when everyone was driven to "know thyself."Your whole self could be understood by the landscape of your scalp, a powerful idea with incredible potential for making the world work better.
Not everyone thought phrenology was a great idea, though. Lots of people thought it was a crazy idea, which is likely where the phrase "getting your head examined" got it's uncomplimentary overtones.