Mr. President and Gentlemen,—The fact of my having been frequently summoned as a medical witness in the civil and criminal courts of justice, in cases in which monomania has been alleged to exist, ana the examination of the evidence in two recent and important cases of disputed wills induces me to bring under the notice of the Medico-Psychological Association the present practice of the Courts in relation to monomania, and to attempt a concise description of this form of disease for consideration and discussion.