INTEREST in the thymus gland as it relates to myasthenia gravis began in 1901, with Weigert's1 report of a thymic tumor observed at necropsy in a patient who had died of myasthenia gravis. Pathologists, notably Bell,2 Norris3 and Miller,4 became actively interested in the subject and were able to find thymic abnormalities in such a high proportion — approximately 50 per cent — of patients who died of myasthenia gravis that some sort of relation of the disease to the thymus gland became established. One of us (Eaton) has previously summarized the evidence for this relation.5 The surgeons did not await the final solution of the problem before attempting to cure patients by removal of the thymus gland. The first surgical efforts, made before satisfactory medical treatment was available, and before the technic of thoracic surgery had advanced to its present status, were failures. With