IN THE year 1952 we reported1that three procedures had been tried in attempts to influence beneficially the tremor of paralysis agitans: (1) interruption of afferent pathways in the midbrain tegmentum (mesencephalotomy), (2) reduction of the impulses passing from the thalamus to the striopallidum (thalamotomy), and (3) reduction of the pallidofugal impulses by lesions of the ansa lenticularis (ansotomy1). While unilateral interruption of the afferent impulses in the midbrain was unable to significantly diminish the tremor and thalamotomy had, at the most, only a slight effect for a few days, a definite reduction of the tremor could be obtained by ansotomy. In order to interrupt the pallidofugal fibers, Meyers2entered the third ventricle and incised its lateral wall. The author reports a favorable effect upon the tremor, but in view of his high mortality he considers the risks of this operation too great to warrant its general