One of the toxic manifestations that has followed the clinical use of sulfanilamide and some of its derivatives is what has most commonly been called peripheral neuritis. Although not so dangerous or so frequent as certain other toxic symptoms produced by these drugs, this nervous phenomenon has given rise to a certain amount of concern and apprehension. Reactions of this nature are not unknown, for similar symptoms have been produced occasionally by other drugs, such as the arsphenamines. Up to the present time little consideration from an experimental standpoint has been given to the pathologic effects that might arise from a toxic action of these drugs on the brain, the spinal cord and the peripheral nerves. Rosenthal1and Nelson2have conducted such a study with sulfanilamide and sulfanilyl sulfanilamide in the chicken and the rabbit. However, they felt that their data were inconclusive, even those obtained on the