Pulsating exophthalmos, or retrobulbar arteriovenous aneurysm, a lesion first reported by Benjamin Travers in 1809, is a relatively rare condition meriting report whenever seen. An average of about five cases is reported each year. Harkness1collected six hundred and twenty-one cases from the literature in his paper published in May, 1930. An exhaustive review of the literature is not attempted here, that angle of the problem having been dealt with ably by de Schweinitz and Holloway,2later by Locke3and still later by Harkness. Diagnosis of the lesion usually may be made from the patient's history and appearance alone. The history is fairly typical: After trauma resulting in a period of unconsciousness, the patient has failure of vision or blindness in one eye, unilateral exophthalmos and a rushing, roaring sound in the head synchronous with the pulse. Palpation of the eye commonly discloses a thrill, and auscultation,