166 University of California Puhlications in Anaiom.y ["^^ol. 2 



parietal lobe. Thus no such fibers enter the area peri-parastriata of 

 Elliot Smith, the areas 18 and 19 of Brodmann, the areas OA and OB 

 of Economo-Koskinas, or even their area, OBy, called limes para- 

 striatus gigantopyramidalis. (The somewhat different results as 

 regards the latter area obtained previously in my experiments with 

 cats, 1927, are probably due to the difficulties of an accurate delimita- 

 tion of that area in the cat ; on the contrary in the monkey, the limits 

 of the stria Gennari or Vicq d'Azyr can everywhere be easily deter- 

 mined ; see paragraph 6 in this chapter.) No matter how the present 

 experiments varied and what portion of the visual radiation may 

 have happened to degenerate, the cortex receiving degenerated fibers 

 always coincided with a smaller or larger portion of the striate area. 

 In all cases the limits of the striate cortex were strictly observed 

 (figs. 13, 40-42, 55-57, 65, 69, 71-76). It is, therefore, safe to con- 

 clude that the visual projection cortex and the striate area are fully 

 identical. Experiment II appears especially valuable in this respect. 

 Here, although the subcortical injury is larger than in any of the 

 remaining three experiments, because of greater distance of the 

 injury from the occipital lobe and a favorable position of the injury, 

 no deg'enerated association or callosal fibers obscured the picture. 

 This experiment, and the remaining four scarcely leave a doubt 

 as to the absence of any direct or even indirect connections between 

 the subcortical \asual stations and the cerebral cortex save by 

 means of the external geniculo-cortical radiation to the striate area. 

 It appears, therefore, that no reasonable arguments can be advanced 

 against a definite settlement of the long continued dispute as to the 

 question of whether the central visual path does reach a "wide" 

 region of the occipital and perhaps also of the parietal lobe, or 

 whether, on the contrary, it terminates in a comparatively small, 

 sharply delimited cortical area of the occipital lobe. The conception 

 of a "diffuse" projection of the retina upon a wide region of the 

 cerebral cortex or even upon several different and perhaps widely 

 distant regions has no anatomical foundation. The opponents of a 

 single well delimited visual cortical projection area must reconcile 

 themselves with this conception by realizing that there is sufficient 

 room in the striate area for the projection of the entire retina and for 

 the reception of all impulses transmitted from the retina to the cerebral 

 cortex. The special emphasis here put upon the existence of a single, 

 definite visual projection "center" as resulting from the present 

 experiments does not appear superfluous. The fiction of a diffuse or 



