Encephalitis in children has become a comparatively common disease during the past ten years. Judging from the medical literature and the case records of the Children's Memorial Hospital, this is in marked contrast to its rarity before this time. Observations of children in whom such a diagnosis was made during this period seem to indicate that the increased frequency of this disorder is due largely to new or previously unrecognized clinical and pathologic syndromes which are placed under the general head of encephalitis.
Acute nonpurulent inflammation of the brain was recognized by Hayem (1867).1 Werincke (1887)2 described a group of cases as complications of the acute specific fevers. Strümpbell (1885)3 suggested the name polio-encephalitis for a group of cases showing cerebral involvement and pointed out the resemblance to poliomyelitis; in 1891, he described two fatal cases of encephalitis in adults with postmortem examination. He also advanced a