Mumps is typically a harmless disease. Orchitis, which is the only common complication, usually runs a benign course. At times, however, other complications may occur which make the course of the disease a severe one. Osler mentions the fact that six deaths are recorded in the Index-Catalog of the Surgeon-General's Library as having resulted from mumps. Recently other fatal cases have been reported. Death, when resulting directly from mumps, is probably always due to the cerebral complications.
The fact that involvement of the central nervous system may occur in mumps has long been recognized, the first fatal case having been reported in 1758 by Hamilton. Approximately one hundred and fifty cases of cerebral complications, exhibiting quite a variety of symptoms, have been reported. Acker1 summarized the literature up to 1913 and added two cases of his own, one with death and necropsy. The nature of the cerebral complications has been