Braid went to a mesmeric demonstration in Manchester in November 1841 intending to catch a fraud. He satisfied himself instead that the subjects really were in an unusual state, and then did something no mesmerist had done: he separated the observation from the explanation. If the state was real, he reasoned, it did not follow that any fluid had passed from operator to subject, and he tested this by having people fix their gaze on a bright object held slightly above the line of sight, with no passes, no magnets and no operator claiming to project anything. They went under. From that he concluded that the cause lay in the subject's own nervous system, in sustained attention and the expectation attached to it, and that the operator merely provided the occasion. He coined neuro-hypnotism for the state, from the Greek for sleep, and later regretted the name, since the state is not sleep, but by then it had been shortened to hypnotism and had stuck.
The full account appeared in Neurypnology in 1843. The move cost him the mesmerists, who regarded the fluid as the whole point, and it did not immediately win him the medical establishment either, which was inclined to treat anything descended from mesmerism as disreputable. He spent the rest of his career arguing on both fronts at once, and the term he coined outlived nearly everyone in the argument.