OPERATIONS on the sympathetic nervous system for the relief of progressive hypertension have been followed by interesting reactions. A decided decrease in blood pressure is the object of the operation. However, it was early noticed that a too sudden and prolonged decrease in blood pressure had the effect of shock on the patients. This occurred during and after the operation. The subjective effect was that of prostration and weakness to the extent that these two factors interfered with convalescence, and the second-stage procedure, which usually is done a week or 10 days after the first, was delayed. Blood was transfused during and after the operation, and the patient's condition was improved. It seemed to us that the intravenous administration of plasma or a plasma substitute would give the necessary support of blood volume that the transfusion of blood had given, inasmuch as there was little loss of blood during this