THE CLINICAL picture generally associated with pheochromocytoma is one of paroxysms of hypertension with normal blood pressure in the intervals between attacks. That chronic hypertension may be produced by pheochromocytoma is well understood.1However, I intend to emphasize the importance of considering such a lesion as a real possibility in all cases of hypertension, especially when the explanation of the symptoms and the hypertension is not completely satisfactory. The outcome in the patient afflicted with a pheochromocytoma is invariably fatal if the tumor is not removed. The hypertensive crises in those with a history of paroxysms become more and more severe until death results from a violent crisis. The organic cardiovascular changes in the person with chronic hypertension due to pheochromocytoma may not cause death as soon as those which occur in the paroxysmal type, but the outcome is as inexorably fatal. Every precaution must be taken to diagnose