Chronic neurogenic hypertension and cardioacceleration was produced in dogs by section of the moderator nerves. Hypertension was found to endure to a considerable degree without cardioacceleration when the sympathetic nerve supply of the heart was interrupted by bilateral removal of the thoracic sympathetic chains (T1 to T9). The same procedure, omitting excision of the stellate ganglia, did not produce decrease in either blood pressure or heart rate. It was concluded that cardio-acceleration plays a definite but minor part in the mechanism of chronic hypertension due to buffer nerve section in dogs.