THE INTRAVENOUS administration of pentothal sodium, an ultra-short-acting barbiturate, is used extensively for the production of clinical anesthesia. The clinical manifestations of cortical depression are evident within thirty seconds after the initial injection. During the action of the drug the patient passes through several phases of depression, depending on the influence of the drug on the various cerebral areas. Brazier and Finesinger1 have shown with the aid of the electroencephalograph a depressant effect of pentothal sodium on the several parts of the cortex. First the frontal area was depressed, then the parietal and, last, the occipital. It has been demonstrated in vitro that barbiturates exert an inhibitory effect on cellular respiration of the brain,2 particularly in the parts of the brain with the highest oxygen intake, such as the more cephalic regions, which suffer the most pronounced metabolic retardation.3
The venous drainage of the cerebral hemispheres and