1932] Poliak: Afferent Fiber Systems, Primate Cerebral Cortex 93 



Helmholtz' theory, attractive in its simplicity, though somewhat 

 reshaped and adapted to modern requirements, has been most widely 

 accepted and is at present the one most recognized, notwithstanding 

 other numerous and quite different explanations. 



Naturally many investigations have been undertaken to test or to 

 reject Helniholtz' theory, among others, by the study of the nervous 

 supply of the cochlea, especially of the organ of Corti. It has justly 

 been assumed that if Helmholtz' theory, an eminently localistic 

 explanation, is right, this would be manifested in a corresponding 

 arrangement of neurons in the cochlea and in the higher links of the 

 auditory path. The early investigators of the nervous supply of the 

 cochlea, Retzius, Gehuchten, and Ramon y Cajal, indeed, found regu- 

 larly arranged ' ' radiated ' ' nerve fibers terminating by small ramifica- 

 tions in the organ of Corti (compare also Ebner). Thus Helmholtz' 

 theory appeared to have sufficient moriDhological support. But, other 

 studies of Held (1897) and Kolmer (1924, 1926, 1927), including the 

 recent studies of Held (1926) and Solovcov (Solovtzoff), finding no 

 "radiated" fibers or only a few, have apparently contradicted Helm- 

 holtz' conception. 



Since Helmholtz' time many other hypotheses have been con- 

 structed (compare Waetzmann, 1926) ; some of them even endeavor 

 to dispense entirely with the necessity of a decomposition of com- 

 plex physical acoustic phenomena into primitive auditory sensations 

 (Rutherford, 1898), or at any rate to place this decomposition in the 

 central organ. All these various attempts, including that of Ewald 

 (1899, 1922), can be said to completely disregard the character of 

 the cochlear nerv^ous supply, which, in view of the contradictory 

 findings of the morphologists, w^as the line of least resistance (compare 

 Barany, 1928, and Bornstein, 1930). 



However, as I endeavored to describe on another occasion in detail, 

 the findings of modern investigators in regard to the nervous supply 

 of the cochlea appear almost as a retrogression in comparison with the 

 earlier results of Retzius, Gehuchten, and Ramon y Cajal. In my own 

 previous studies of the character and mode of distribution of the nerve 

 fibers in the cochlea (1927), I became convinced of the accuracy of 

 the early obser\-ers who demonstrated the existence of isolated 

 "individual" fibers arranged parallel to one another; this stands in 

 good accord with Helmholtz' explanation of the nature of auditory 

 processes. JMoreover, other observations favor the acceptance of a 

 stable projection of the cochlea upon the cerebral cortex though the 



