Stimulation of the corpus striatum by previous investigators has consistently failed to give definitive results. Several technics have been employed. The cortex overlying portions of the corpus striatum has been ablated, and the areas thus exposed have been stimulated. The most recent experiments of this type have been those by Rioch.1The stimulating electrode has also been placed on a stereotaxic carrier and inserted into certain portions of the corpus striatum, notably the pallidum, in the investigations by Wilson.2Grinker3employed another technic, namely, stimulation of the basal masses in cases of anencephaly. He obtained an athetoid type of movement which he regarded as originating in the corpus striatum. We shall have occasion to refer to this type of motion later, but for the present it may be pointed out that of the preceding technics only that of Wilson is above criticism. Stimulation after cortical ablation is