Separately the adjuncts of hypotension and hypothermia have been demonstrated to be controllable and safe. Morris1 induced controlled hypotension by the administration of hexamethonium and found that there was little evidence of cerebral or renal damage due to anoxia in patients kept in the supine position during the period of depression. In these subjects the mean blood pressure was lowered to 55 mm. of mercury. Anlyan2 has studied the extent of liver damage incurred after hypotension induced by ganglionblocking drugs. He and his co-workers compared the changes in liver function induced by hypotension produced by hemorrhage with that produced by ganglion-blocking agents. They reduced the blood pressure to a mean pressure of 30 mg. of mercury for 30 to 45 minutes in dogs by each method and found that the mortality rate was lower when the ganglion-blocking chemical drug was used to reduce the pressure. Histological changes in