A new concept of the physiology and pathology underlying the development of the toxemic state in pregnancy is based on old and new knowledge of the role of body fluids in maintaining the integrity of the organism. A method of treatment is derived from this concept in the light of facts developed in connection with studies on water balance, acid-base equilibrium, renal function and shifts in body water and electrolyte. Newburgh1and his associates have measured water exchange in many persons with normal and abnormal renal function. They found that if the intake of water was restricted in cases of impaired renal function, retention of urinary solids would result. If large amounts of water were given, the quantity of urinary solids excreted would be comparable to the excretion by a normal person ingesting the same diet. From these data they were able to calculate the amount of urinary water