Hypnosis originates from the practice of Mesmerism, being an attempt at what the surgeon James Braid described as "rational mesmerism".
This reflected a new-found interest in spiritualism, to which her parents had turned in the early 1850s, as did her book Pioneers of the Spiritual Reformation (1883), which consisted of biographical sketches of the German poet Justinus Kerner and of her father William Howitt, but whose other purpose was to promote spiritualism, mesmerism and similar phenomena.
In England mesmerism was championed by John Elliotson, Professor of Practical Medicine at University College London and the founder and president of the London Phrenological Society.
His experience of the deception of Okey Sisters’ reputed speaking in tongues with Irving, and his knowledge of their later association with Elliotson and his mesmerism, and their well-attested fraudulent deception of Elliotson, must have strongly informed his later views of the activities of magnetists such as Lafontaine.
Mesmer's ideas became so influential that King Louis XVI of France appointed two commissions to investigate mesmerism; one was led by Joseph-Ignace Guillotin, the other, led by Benjamin Franklin, included Bailly and Lavoisier.