A work written from observations and facts observed in the Salpetriere, in accordance with the experimental method observed in clinical science. Contents: animal magnetism in its beginnings, Mesmer and Puysegur; history of animal magnetism; modes of producing hypnosis; symptoms of hypnosis; hypnotic states; imperfect forms of hypnosis; general study of suggestion; hallucinations; suggestions of movements and acts; paralysis by suggestion, anesthesia; paralysis by suggestion, motor paralysis; application of hypnotism to therapeutics and education; hypnotism and responsibility.