138 University of California Piihlications in Anatomy [Vol. 2 



striate cortex de-afferented in such a way was slightly larger, it was 

 in part identical with the lesion (c). The third small injury (d) 

 also slightly reaches into the white subcortical substance, but is other- 

 wise well delimited ; this lesion can also be considered as an equiva- 

 lent of a purely cortical lesion since it is located at a considerable 

 distance from the sagittal strata of the occipital lobe and, conse- 

 quently, interrupts merely a bundle of fibers streaming into the cor- 

 tical segment indicated by (d) and, at most, into its nearest vicinity. 

 The fourth and largest injury (a) not only destroys directly a consid- 

 erable portion of the macular cortex in the upper and central half 

 of the macular region including the tip of the occipital lobe behind 

 the calcarine fissure, but penetrates as well into the white substance 

 where it interrupts fibers destined for the striate cortex lining the 

 ascending branch of the calcarine fissure (its posterior lip). 



The left external geniculate body studied on sections of a contin- 

 uous series stained according to Nissl's method (left eight figures in 

 fig. 18), in agreement with the number of the lesions, showed also 

 four distinctive zones where the cells degenerated : one large, and 

 three small ones. The large zone, (a) appears on most oral sections 

 as a narrow triangle in the upper portion of the nucleus pointing 

 with its sharp angle toward the hilus of the nucleus without, however, 

 reaching it (1 in the left upper corner). This zone on subsequent 

 caudal sections becomes gradually larger in width and extends farther 

 down to the hilus and finally reaches the ventral layers containing 

 large cells (2-7 in the first and second row from the left). On the 

 whole, this degenerated zone remains strictly confined to the inter- 

 mediate or macular segment of the lateral geniculate body. The three 

 small degenerated zones, corresponding with the three small lesions of 

 the most anterior portion of the opercular striate area (which we can 

 consider the "posterior" limit of the striate area, if we imagine the 

 occipital pole pushed back and attaining the position on the tip of the 

 occipital lobe, as found in human brain) appear only in the posterior 

 half of the lateral geniculate body {h, c, d in 6-8 in the second row 

 from the left). At first appear two small wedge-shaped zones in the 

 tip of the nucleus {h, c, in 6, second row from the left). Both zones 

 are triangular in shape, pointing with their sharp angles toward the 

 hilus of the nucleus without reaching it, or merging with the vestige 

 of the large zone (a) confined here to the lower portion of the inter- 

 mediate segment of the nucleus and just reaching the hilus. On the 

 sections farther caudal the third small degenerated zone appears [d in 



