Initially, Braid believed the state was caused by physical fatigue of the eyes and nervous system from fixed staring.
James Braid’s seminal work, Neurypnology; or, the Rationale of Nervous Sleep (1843), is considered the foundational text of modern hypnotism. In it, Braid moved the field away from the mystical "animal magnetism" of Franz Mesmer toward a physiological and scientific understanding of trance as a state of "nervous sleep". Core Principles of Neurypnology
Experts and historical archivists highlight Braid's unique contribution to the transition from occultism to medicine:
Braid’s work focused on the physical and psychological mechanisms that induce a hypnotic state:
James Braid | Health and Medicine | Research Starters - EBSCO
“He recognized that hypnosis was a subjective phenomenon, dependent entirely on the state of mind of the hypnotized and not on any mystical fluid or occult magical power wielded by the hypnotizer.” Peter Harrington Recommended Versions of the Article
The Wood Library-Museum of Anesthesiology provides a complete digital copy of the 1899 edition, which includes Waite's extensive biographical introduction.
“I regard this book as THE fountain head of hypnosis. Braid not only gives us the word we now use for our subject, but brought to it a clarity of thought and an energy of experimentation which is unparallelled.” Ragged University
