For many years the occurrence of simultaneous pathologic processes in homologous twins has aroused the curiosity of medical men. Recently it has been realized what interesting side lights such cases throw on both the etiology of disease and on genetics. Reports of such cases have been numerous in the literature. Many pairs of homologous twins have been born with identical developmental defects.1 Others have almost simultaneously had various neoplastic diseases in middle or late life. Still others have had certain metabolic diseases, such as diabetes, within a few months of each other.2 Other twins have had identical psychic disturbances varying from actual psychoses to similar alcoholic propensities.
It has been our privilege to observe mitral heart disease, following rheumatic fever, in each of identical twin girls. Since the case brings out some interesting points and since a survey of recent literature showed no similar case, we felt that