1. Correlative data on EEG changes, behavioral alterations and variations in blood alcohol level were obtained in 3 former narcotic addicts, without anamnestic, neurological or EEG evidence of central nervous system disorder, who received averages of 458-489 cc. of 95% ethyl alcohol daily for 48-55 days, followed by abrupt withdrawal of the drug, under controlled experimental conditions.2. During chronic alcoholic intoxication, blood alcohol levels varied with particular procedures that were carried out, but were maintained for long periods at about 200 mg. %. Initially, EEG's were diffusely slowed, and this change persisted in milder degree during the remainder of the chronic intoxication period. However, EEG evidence of partial, though precarious, "metabolic" and "tissue" tolerance was obtained, which corresponded roughly to variations in degrees of behavioral intoxication.3. By the 15-19th hour of abstinence, blood alcohol levels had fallen to zero. Anxiety, tremulousness, weakness and profuse perspiration were exhibited by all subjects, and transient, mild but definite dysrhythmias were noted in the EEG. In addition, one subject developed transitory visual hallucinations, and at the 41st hour of abstinence, a generalized seizure. Another developed hyperreflexia, tachycardia, elevation of blood pressure, fever, nausea, vomiting and diarrhea with transitory hallucinosis during the first 2 days of abstinence, and classical delirium tremens on the 4th day. No specific EEG change could be correlated with such mental changes. All subjects recovered fully within 3 weeks after abrupt withdrawal of alcohol.4. It is concluded that "rum fits" and delirium tremens can be precipitated by abrupt withdrawal of alcohol in persons continually intoxicated for 48 days or more, that these phenomena may develop in individuals without evidence of pre-existing disorder of the central nervous system, and that alcohol is an addicting drug in the sense that it can produce pharmacological dependence, both "psychic" and "physical."5. The clinical and electroencephalographic changes that occur in cycles of addiction to alcohol and barbiturates are compared and contrasted.