The technique of measuring the pressure within the internal jugular vein and carotid arteries has already been described. The purpose of this paper is to report the effect of certain drugs on the cerebrospinal fluid, internal jugular venous and arterial pressures in man.The only anesthetic utilized was novocaine to desensitize the skin preparatory to the puncture of the internal jugular vein and the lumbar subarachnoid space. The subjects chosen were patients having some type of psychosis. None had any definite cardiovascular disease.