1. A picture resembling acute disseminated encephalomyelitis in the human being has been regularly and rapidly produced in rhesus monkeys by injection of emulsions of adult rabbit and monkey brain administered with adjuvants.
2. No lesions of the central nervous system resulted from injection of similar emulsions of fetal rabbit brain or adult rabbit lung.
3. A description of the gross and histological findings in the central nervous system is given and compared with features of human demyelinating disease.
4. The experimental findings are in accord with the hypothesis that antibody to the injected brain emulsion reacts with the tissues of the nervous system of the animal to produce the pathological changes.