. Biology of the vertebrates : a comparative study of man and his animal allies. Vertebrates; Vertebrates -- Anatomy; Anatomy, Comparative. According to the most generally accepted theory of hearing, a modifica- tion of the resonance theory proposed by Helmholtz many years ago, any given frequency causes most vigorous movements of only a localized area of the ribbon-like basilar membrane. There is thus a place on the membrane for each pitch (or frequency) ; hence, this is known as the place theory of hearing. Striking of the hair-cell "hairs" of the affected region against the tector
. Biology of the vertebrates : a comparative study of man and his animal allies. Vertebrates; Vertebrates -- Anatomy; Anatomy, Comparative. According to the most generally accepted theory of hearing, a modifica- tion of the resonance theory proposed by Helmholtz many years ago, any given frequency causes most vigorous movements of only a localized area of the ribbon-like basilar membrane. There is thus a place on the membrane for each pitch (or frequency) ; hence, this is known as the place theory of hearing. Striking of the hair-cell "hairs" of the affected region against the tectorial membrane stimulates their associated nerve endings. Impulses car- ried by certain fibers of the cochlear nerve are then interpreted by the cerebral cortex as particular tones. In support of this theory is the work which has shown that the higher audible frequencies stimulate fibers asso- ciated with the basal part of the cochlear duct, where the basilar membrane is narrowest, while low frequencies affect the apical region where the membrane is widest (Fig. 702). The amplitude of the vibrations determines the loudness of the tones produced, while the pitch, whether it be high or low, is correlated with the frequency, or relative number of vibrations per unit of time. The quality, or timbre, of a tone, by which the difference between a human voice and a violin, for example, is detected when producing the same musical note, is dependent upon the character, or shape, of the sound waves when visually recorded, as also upon the overtones, or accompanying sympathetic vibra- tions of different harmonious nodal lengths which may be added to the. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Walter, Herbert Eugene, b. 1867; Sayles, Leonard Perkins, 1902-. New York : Macmillan Co.
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