IN USING the term "optic neuritis," I refer both to the intraocular and the retrobulbar varieties, in other words, to papillitis as well as to retrobulbar neuritis. Wilbrand and Sanger divided optic neuritis into three main classes: perineuritis, axial neuritis, and transverse neuritis. Traquair1 quotes Wilbrand and Sanger and uses this classification in his descriptions. Duke-Elder2 also makes use of this classification, explaining further that in using the term "optic neuritis" he means to include the intraocular form, i. e., papillitis, as well as retrobulbar neuritis, in which no fundus changes are shown. He then speaks of a type of neuritis that occurs within the anterior portion of the optic nerve, close to the disc, describing it as showing slight edema of the nerve head. Walsh,3 in his textbook on neuro-ophthalmology, also uses the Wilbrand and Sanger classification but deviates somewhat from the usage of the terms