The title of this work has reference to the classical allusions of Homer and Virgil to spectres which walked through the ivory gate. It contains extremely interesting accounts of the lives of several famous and infamous persons, all of whom the author believes to have been the victims of " spectres." The individuals under consideration are Emanuel Swedenborg, William Blake, Louis II of Bavaria, Chas. J. Guiteau, Louis Riel, Gabriel Malagrida, and Thebaw, King of Burmah. The author's graphic descriptions of the character and lives of these insane persons, as he believes them to have been, furnish most interesting and valuable descriptions of some phases of insanity.