Phineas Gage, a railroad construction foreman, suffered a traumatic brain injury in 1848 when an iron rod was propelled through his head by an explosion. Though Gage survived for over a decade after the accident, the tamping iron's journey through his brain had a dramatic effect on his personality and behavior, turning him from a polite, even-tempered man into one who was irritable and profane. The document provides biographical details on Phineas Gage and quotes a description of his personality change from Dr. Harlow, who knew Gage before and after the accident.