SINCE Schilder's description of "Encephalitis periaxialis diffusa," the study of a fairly great number of cases has led to the general acceptance of this histologically well-characterized picture as an early stage of diffuse sclerosis. It is evident that for elucidation of the pathogenesis of this disease knowledge of its early stages is required. So far only a single case with a fulminating course and fatal outcome has been described (Case 3 of Stewart, Greenfield, and Blandy1). The case to be reported here was characterized also by a fulminating course and seems important to the general aspect of the pathogenesis and classification of Schilder's disease. REPORT OF A CASE A. K., a woman born Sept. 12, 1929, a tailor's apprentice, was admitted to the department of neurology and psychiatry on Jan. 31, 1950. The family history, taken from her brother-in-law, revealed nothing relevant to her present illness. Her somatic and