1932] Poliak: Afferent Fiber Systems, Primate Cerehral Cortex 13 



and of a multiple cortical representation of the retina including the 

 macula, according to different architectural and functional principles 

 (ideas at present regarded by the majority as obsolete) ; he even 

 doubts the existence of any finer projection of the peripheral visual 

 receptive surface upon the cerebral cortex. There should be, Gold- 

 stein thinks, no reason for accepting a strict correspondence between 

 each of the retinal segments and those of the striate area. He believes 

 that in the visual system "only a relatively roughly delimitable pro- 

 jection has been evidenced and can be proved." It is true that con- 

 trasted with the abundance of pathological and clinical observations 

 on visual disturbances in cases with various injuries of the occipital 

 lobe, very little investigation of the visual radiation and visual cortex 

 in man by anatomical methods, especially by secondary degeneration — 

 which would really clarify the entire central visual mechanism — has 

 been made. Furthermore, a systematic experimental anatomical inves- 

 tigation of the internal arrangement of the visual radiation in higher 

 mammals (primates) is conspicuous by its complete absence. It is 

 especially remarkable that no attempts have been made hitherto to 

 analyze the finer organization of the central portion of the visual 

 apparatus by experiments with monkeys (the peripheral portion was 

 studied by Brouwer and Zeeman).^ Some hints in this respect were 

 obtained by anatomical studies of human pathological material with 

 more or less limited injuries (Henschen, Quensel, Monakow, Zingerle, 

 Winkler, Brouwer, Niessl von Mayendorf, Putnam, et aL). On the 

 other hand, studies of normally stained preparations of human hemi- 

 sphere (Flechsig, Henschen, Probst, Niessl von Mayendorf, La Salle 

 Archambault, Brouwer, Putnam, R. A. Pfeifer), valuable as they were 

 for the comparatively gross features of the visual radiation, proved 

 insufficient for the explanation of its minute, internal organization 

 and in particular of the projection of various quadrants of the retina 

 and especially of the macula upon the cerebral cortex (see Flechsig, 

 1927, p. 93). It seems certain, therefore, that a thorough and sys- 

 tematic study of the central portion of the visual apparatus in respect 

 to its peripheral portion after the manner of Brouwer and Zeeman 

 and their collaborators, is required before any clear view can be 

 attained as to how and where the various retinal quadrants are exactly 

 projected and how they are represented in definite segments of the 

 \'isual radiation and in the visual cortex. The number of detailed 



1 In this respect much has been gained from the recent experiments of Brouwer 

 and Heuven. 



