The changes in circulation following the use of alcohol are probably more universally recognized than those produced by any other drug. Nevertheless, the circulatory effect of alcohol in the body is difficult to analyze, because it is the resultant of a number of direct and reflex effects both on the heart and on the blood vessels in different vascular areas. In order to evaluate properly the action of alcohol on a given vascular bed, such as the cerebral circulation, it is desirable to review briefly the facts already known about its circulatory effects. There is general agreement that large doses of alcohol1administered intravenously produce an abrupt fall in blood pressure with cardiac slowing or standstill, followed by rapid recovery (Dixon2decerebrate cats, dogs and rabbits; Brooks,3unanesthetized dogs and Hyatt,4unanesthetized dogs with transections of the lower thoracic portion of the cord). Neither fall in