About the middle of 1917, there was reported by von Economo1 a number of cases, appearing in Vienna, in apparently epidemic proportions, characterized by somnolence almost simulating sleeping sickness, and ending sometimes after a few weeks or even months in death. The prodromes were headache, nausea and vomiting, suggesting a general infection or intoxication. In addition to these general symptoms, the frequency of the simultaneous involvement of some of the cranial nerves, manifested by ophthalmoplegias, such as ptosis and facial palsy, suggested a localization of the disease in the brain. Examination of the spinal fluid threw very little light on the nature of the disease, the cells in most cases being within normal limits, and repeated bacteriologic examinations yielding no positive results. In addition to the involvement of isolated nuclei of the bulb, there were, in some other instances, other signs of cerebral involvement, such as ataxia and tremor,