Phineas Gage was a railway worker who survived an accident that blew a large iron rod through his brain in an accidental explosion in 1848. The subsequent brain injury changed his personality from friendly to belligerent, a phenomenon that challenged the then accepted theory of personality, and opened people’s minds to the idea that the physiology of the brain was involved in personality and disposition.
The above photo- the only known photo of Phineas Gage- was recently identified after being posted on Flickr by its owners, who, not realizing who the subject was, had titled it “One-eyed man with harpoon”. A random internetter correctly identified the photo’s subject in a Flickr comment, supposing that the “harpoon” he held might actually be the iron tamping rod that had injured him. Awesome. Here’s lots of info in a solid post on Metafilter. Internet for the win.