Mark Twain in his sixty-fourth year and with a long history of physical complaints underwent osteopathic treatment. He found relief from many symptoms, gained 'mental and physical refreshment', and became enthusiastic about the methods employed. A brief study of his writings, of his personal history, and of the comments of various friends about his hypochondriacal and pessimistic 'affectations' gives grounds for considering Mark Twain as having compelling reaction-formations to opposing unconscious sadistic drives. Incidents from his life and instances from his literary composition are adduced for this conclusion. His osteopathic 'cure' is a point of departure for these observations.