This work is a monographic account of acute carbon monoxide poisoning, with a special consideration of neurologic sequelae. After a general review of the subject, the author presents a series of 1,304 cases with follow-up study. This series is analyzed with respect to the source of poisoning, sex and age, pathologic conditions existing in the patients before the intoxication, the degree and duration of the impairment of consciousness, acute neurologic symptoms, cerebrospinal fluid findings, immediate causes of deaths (6.1 per cent), postmortem cerebral findings and the residual neurologic changes in the survivors. Neurologic complications developed in 2.1 per cent of the cases, and the histories of these are given. This incidence is about the same as that reported by other observers. The neurologic symptoms are described in considerable detail. From his analysis the author believes that the acoustic, hemiplegic and neurasthenic syndromes are more frequent than previously supposed, while the