This study was prompted by the definite increase in the number of cases of polyneuritis which we have observed in the past three years. We are cognizant of the confusion that exists in the literature regarding the terminology of polyneuritis and shall avoid entering into a discussion of the merits of the numerous terms which are employed to describe what appear to be minor variations of the same disease process. We propose to consider in this study a series of cases which have been encountered at the Mayo Clinic in the last fifteen years. These, we believe, can be classified under one heading and should be isolated from the large group of cases of polyneuritis in which the condition is due to various and sundry causes. We have adopted the term "neuronitis" to designate the disease in this series of cases. While certain peculiarities, such as facial diplegia and choked