[Gr. hypnos, sleep.] The science of what was once called mesmerism and animal magnetism. The subject in a hypnotic state comes under the sole control of the operator, and acts under his suggestions, which seem reality to the patient. It is said that suggestions to perform a certain act at some future time will be obeyed, and in this way a criminal act might be done for which only the operator was responsible, the patient ceasing to be a free agent. Hypnotic suggestion is now used as a remedial agent, patients being induced to give up drinking, to cease other hurtful practices,to perform useful exercises or become diligent in study, etc. Also painful sensation is obviated, so that surgical operations can be performed without suffering.