When Sjöqvist1introduced tractotomy for the relief of trigeminal pain, the first cases in which operation was performed were those of postherpetic neuralgia and of painful anesthesia following section of the trigeminal root. For some time hesitation was felt in applying the new procedure to true trigeminal neuralgia, since section of the sensory root carries little risk to life and pain as a rule is permanently abolished. A follow-up study2of the 313 cases of trigeminal neuralgia in which operation had been performed in this clinic up to July 1, 1938 revealed that the late results were not quite so brilliant as had been supposed and particularly that the disability and discomfort due to complete or nearly complete anesthesia in the greater part of the trigeminal area were considerably underestimated. Since tractotomy held out the promise of relief from pain with conservation of tactile sensation, it was decided