There are several reasons suggesting that a hemolytic agent of placental origin may be of essential importance in eclampsia. The occurrence of methemoglobinuria, the possible relation of the hepatic thromboses to hemolyzed red cells, the resemblance between the eclamptic lesions and those produced by the injection of eclamptic serum or of immune hemolytic serum in rabbits, the possible origin of the eclamptic toxin from the placenta which normally possesses a hemolytic ferment, the marked hypertrophy and desquamation of the syncytium at term and during labor, and the relief of the symptoms in many cases as soon as the placenta is removed, all tend to indicate a hemolytic agent derived from the placenta as a factor in the disease.In order to obtain some information regarding this subject I examined the placenta in fifteen cases of eclampsia, and the circulating blood and the viscera of several fatal cases for evidence of hemolysis. If any marked degree of hemolysis had occurred during life one would expect...