Abstract
In anaesthetized dogs at room temperatures of 28-33 degrees C, the cerebral ventricles were perfused with artificial CSF from the left lateral ventricular to the aqueductal cannulae. The animals' temperatures were recorded from the rectum. Addition of Ca(++) in excess to the artificial CSF perfusing the ventricles produced hyperthermia and addition of Na+ in excess produced hypothermia. Perfusion with medium deficient in Ca(++) and containing sodium edetate produced hypothermia. The temperature effects of Na(+) or Ca(++) in excess were mutually antagonistic.