The frontal, parietal and occipital lobes have been cut away from the left hemisphere and branches of the anterior, middle and posterior cerebral arteries have been left in situ. In the center of the hemisphere the white mass of the corona radiata (21) remains. No attempt was made here to dissect individual systems of fibers in this region inasmuch as these are demonstrated in dissections shown elsewhere. The contents of the lateral fissure have been disclosed by the resection of the frontal and parietal opercula. The upper half of the insula (11) is exposed and the circular sulcus can be seen around its periphery.