In 1938 Sjöqvist,1Stockholm, Sweden, described a new operative procedure for the relief of facial pain which was based on, and took advantage of, the peculiar anatomic and physiologic features of the intramedullary fibers of the trigeminal nerve. Briefly, the method involves the making of an incision into the lateral aspect of the medulla oblongata, about 3.5 mm. deep and 3.5 mm. long, and so placed as to transect the descending tract and spinal nucleus of the trigeminal nerve. In this way, half of the face is rendered analgetic and thermanesthetic, since the fibers for pain and temperature sense course in the descending tract. Tactile sensation, however, is not grossly disturbed because practically all the fibers conveying touch sensation terminate immediately in the main sensory nucleus of the trigeminal nerve, after entry of the nerve into the brain stem. The introduction into neurosurgical practice of such an unusual innovation