Professor Chalmers is distinguished for his contributions to the elucidation of the nervous mechanisms responsible for control of blood pressure in normal and hypertensive people. He was first to demonstrate the importance of nor-adrenergic nerves within the brain itself in the control of blood pressure and in the pathogenesis of all forms of experimental hypertension. These studies, and his definition of the roles of other central nervous system transmitters, have provided a rational basis for understanding control of blood pressure in man. He has introduced new approaches to treatment involving the use of drugs which act on these central nervous transmitter systems.