The ill effects on the nervous system of the use of foreign serums injected for therapeutic purposes have been recognized since the early years of the century, the first case having been reported in 1908 by Gardère and Gangolphe.1Since then it has slowly become evident that the meninges, the brain, the spinal cord, the spinal roots and the peripheral nerves, both cranial and spinal, may be the site of more or less severe disease, producing a variety of syndromes, which as a rule subside, leaving few if any residua. Both the somatic and the visceral nervous system are affected. The clinical pictures, the pathologic basis and the questions of etiology and prognosis have gradually been clarified. Reports of cases have accumulated in the United States, France, England, Belgium, Switzerland, Germany, Italy and Czechoslovakia. The greatest number are from France, no doubt stimulated by the report of three cases