The occurrence of unilateral tonic*seizures as a part of the clinical picture of multiple sclerosis was recently reecognized by Matthews.1Earlier reports on epilepsy occurring in patients with multiple sclerosis have occasionally mentioned tonic spells, but have failed to recognize their significance as a specific manifestation of this disease. It appears that tonic seizures when occurring not as a sign of decerebration, as during a phase of increased intracranial pressure or extensive brain stem disease, should raise the diagnostic possibility of multiple sclerosis. The history, physical findings, and pertinent laboratory studies on 4 patients with this unusual finding will be described. Report of Four Cases Case 1.—A 25-year-old man was seen for the first time at the University Hospitals on Jan. 24, 1961. He had been well until the age of 19 years, when he had the first series of attacks of tonic seizures involving the left arm,