In this report are analyzed the cases of eclampsia treated at the Chicago Lying-In Hospital from July 1, 1917 (when the new hospital was opened), to Jan. 1, 1926. During these eight and one-half years there were 29,587 obstetric patients. Of this number, 20,226 were delivered in the hospital and 9,361 were delivered at home by our dispensary service. Among these 29,587 patients there were eighty-three who had eclampsia, an incidence of 0.28 per cent. Five of these women who were delivered at home were colored and were sent to other institutions. The remaining seventy-eight patients with eclampsia were admitted to the Chicago Lying-In Hospital, and a study of these cases forms the basis of this paper. OBSERVATIONS Definition. —I consider as eclampsia all cases, showing the typical signs and symptoms of acute toxemia including convulsions, in which medical causes like epilepsy and other diseases can be ruled out, and