A multiple neuritis of unknown origin characterized by its frequent association with infection of the respiratory tract, increased protein in the spinal fluid without an increase in the cell content, frequent involvement of cranial nerves and a benign course was described by Guillain, Barré and Strohl1 in 1916. The clinical distinction between this syndrome and other neuritides, frequently designated as Landry's paralysis (acute ascending myelitis), peripheral neuritis with facial diplegia, acute infective polyneuritis, acute febrile polyneuritis, infective neuronitis, acute ascending paralysis and myeloradiculitis, is not sharply defined (De Jong2). No pathologic anatomy was described either in the original or in subsequent observations of Guillain,3 who insisted on a uniformly favorable outcome as an essential diagnostic criterion. However, pathoanatomic reports with emphasis on the peripheral nervous system are available of the same disease, or at least of closely allied disorders, but little is known of the condition of