218 University of California Puhlications in Anatomy [Vol. 2 



a conclusion, however risky this mig'ht appear and difficult to solve, if 

 we consider the advanced structural differentiation of the human 

 cortex as compared with that in lower mammals (consult Brodmann, 

 Ariens Kappers, Herrick, 1926, and Economo-Koskinas). Neverthe- 

 less, as previously stated, the difficulty here is not only in discovering 

 special structures, the substrata of particular primitive functions, 

 but also in determining: and in defining of those primitive or elemen- 

 tary processes to be localized. Be this as it may, advance in the dis- 

 entanglement of these intricate problems may be expected from 

 further investigation of the organ of the mind itself and by improved 

 methods of study rather than from elaborate speculation (A good 

 presentation of the problem of localization of "higher" cerebral func- 

 tions one finds in Isserlin's and in Economo's [1929] papers.) 



moreover, a necessary prerequisite for the preservation of the \dsual "figures" up 

 to the striate area, the latter apparatus, thanks to its organization, is endowed with 

 the ability of reacting in most varied ways. Because of this, the conception of 

 fixed and unalterable relations between individual \nsual ' ' figures ' ' (and ' ' images ' ' 

 as well) on the one hand, and definite groups of neighboring ganglion cells on the 

 other, as alleged by some localists, does not appear to be appropriate. It appears 

 more probable that in most of the visual receptive (and perceptive) acts, a large 

 number of cortical cells are activated. Some or many of these same cells are 

 involved at a different time in different receptive processes (different combinations 

 of the same cells produce central "figures" totally different from the preceding). 

 This is more probable since in view of the small size of the macular cortex, most 

 of the "figures" produced here will necessarily expand over the greater part or 

 occupy almost the entire macular cortex. A similar property, the ability of the 

 same nervous elements to react to the most varied stimuli, has to be attributed 

 even in a. greater degree to the visual association areas (fields 18 and 19, area peri- 

 parastriata) which have, on the whole, a different function than that of the striate 

 area (field 17). Considering also the small size of the peri-parastriate area in 

 the monkey, it is more appropriate to think that most of the visual and composite 

 "images" are bound to structures distributed over a large part of the mentioned 

 area. (In these speculations the following fact has been taken into consideration: 

 in monkeys, which undoubtedly have a very well developed "visual memory," 

 because of the comparatively small size of the peri-parastriate area which is 

 hardly larger than the striate area, the striate area must also actively participate 

 in the so-called "higher" visual processes, and cannot be a mere "through sta- 

 tion" or a "switchboard" for the incoming impulses). That the striate area, acts 

 more-or-less in its totality in certain functions has been well demonstrated by 

 Kliiver's experiments with monkeys. 



