The presence of an edema of the brain in many instances of delirium tremens and its absence in many brains of patients dead of the same condition is well known. As yet, however, a satisfactory explanation of the presence or absence of this edema has not been found. Following the enforcement of the Harrison Narcotic Law, many drug users turned to alcohol as a substitute. A notable increase in the number of patients suffering with delirium tremens has been the result, and the availability of a number of bodies for post-mortem examination has prompted this study. In considering this question it has seemed that two hypotheses are especially worthy of investigation: First, is the presence or absence of brain edema entirely dependent on conditions within the brain cells themselves? Or, second, is the presence of an edema dependent on the availability of fluid? That is, may the brains of delirium