“I'm sure we're going to find out one day that the brain is as worthless as the appendix.” —Scott McClanahan The poor, maligned appendix. That worm-like accessory dangling from our intestines has long ...

For years, the appendix was brushed off as a useless leftover from human evolution. Many of us grew up believing that it served no real purpose and was better off removed at the first sign of trouble.

Most people know only two things about the appendix: You don’t need it – and if it bursts, you need surgery fast. That basic story traces back at least to Charles Darwin, the English naturalist who ...