Hughlings Jackson's Second Thoughts on Mental States in Epilepsy.

John Hughlings Jackson (1835-1911) was the pre-eminent British neurologist of the last 3 decades of the 19th century whose most seminal contributions related to the understanding of epileptic seizures. Jackson instructed that his personal papers should be destroyed at his death, and consequently, few examples of his handwriting now survive. We discovered a series of marginalia in Jackson's handwriting annotating one of his papers, "On temporary mental disorders after epileptic paroxysms," first published in 1875 in the West Riding Lunatic Asylum Medical Reports. Two of the most extensive annotations indicate Jackson's later understanding of "epileptic vertigo" and of "mental automatisms." We contextualize the changes in Jackson's thinking suggested by these emendations. These marginalia give insights into Jackson's continuing effort to understand epilepsy and its implications for brain function, an issue that was then, as now, one of the fundamental problems in neurology.