1. Simultaneous comparisons were made between the mental state and the EEG changes induced by intravenous barbiturates in subjects with and without organic brain disease.2. Normal subjects did not become disoriented following intravenous sodium amytal and the EEG effects were the same as those noted by others.3. Although disorientation often followed the drug in subjects with structural lesions and normal records, the EEG changes were not different from those occurring in controls. In abnormal records, there was a reduction or disappearance of slow activity after the drug concomitant with the development of an organic mental syndrome.4. Focal abnormalties were occasionally elicited, or, if previously present, accentuated by the drug.5. Under the conditions of the experiment, the mental state did not parallel the state of the EEG. Possible reasons for this discrepancy are discussed.Abstract Teaser