On September 13, 1848, Phineas Gage was packing a blasting charge near Cavendish, Vermont, when the powder went off and drove his tamping iron through his head. The rod was three feet seven inches long, an inch and a quarter in diameter and weighed thirteen and a quarter pounds. It entered under his left cheekbone, passed behind his left eye and out through the top of his skull, landing many feet away. He was 25. He was foreman of a crew building the Rutland and Burlington Railroad.
He did not lose consciousness, and by most accounts he was talking within a few minutes and walked to a cart. Harlow found him sitting up. The local physician, Dr John Martyn Harlow, had been sent for and found him in a chair outside a hotel, able to describe the accident. Harlow treated the wound, which drained and became infected, and Gage recovered over the following months, blind in the left eye but otherwise mobile.
The case became famous because of what was said to have changed. Harlow's account, published in 1868 after Gage's death, described a man who had been efficient and well-balanced before and was afterwards fitful, irreverent, profane and unable to keep to a plan, and he summed it up as Gage no longer being Gage. That description is the origin of the modern idea that the frontal lobes are where personality and the capacity for judgement live, and it is in every textbook.
It is also largely reconstruction, and this is worth saying plainly. Almost nothing was recorded about Gage between 1848 and his death, and the anecdotes about fits and impulsiveness come from a handful of later sources of uncertain reliability. Some of them describe a man who travelled, kept a job driving coaches in Chile for several years, and managed a livery stable, which is not the behaviour of someone wholly incapable of planning. The honest summary is short. He survived damage to both frontal lobes. His friends thought he had changed.
Gage died in 1860 after a series of seizures. His skull and the iron were exhumed and are at the Warren Anatomical Museum at Harvard. A CT scan of the skull done in 1994 by Hanna Damasio and colleagues reconstructed the path of the rod and confirmed that both frontal lobes had been damaged, with the left more severely affected than the right.