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On the Recognition oj Noises. 
[June, 
VI. ON THE RECOGNITION OF NOISES. 
N an examination of the question with what part of the 
auditory organs we recognise noises, S. Exner, as 
far back as 1876, came to the conclusion that we 
perceive them with the cochlea and by means of the same 
tissues with which;we hear sounds, that is by the Corti’s 
fibres resting upon the basilar membrane of the cochlea and 
containing the terminal expansions of the auditory nerve. 
He founded this view upon Seebeck’s experiment, in which 
a Savart’s wheel from which so many of the teeth had been 
removed that it no longer gave out a sound, but merely a 
noise, still occasioned the feeling of an elevation of sound 
when it was made to revolve with greater velocity. He 
further caused two electric sparks to strike in succession, 
and on reducing the interval between them he recognised in 
the noise an elevation of tone. 
Von Helmholtz, in the fourth edition of his “ Treatise on 
the Perception of Sound” (Lehrevon den Tonempfindungen), 
adopts Exner’s view. He assumes that a single impact, if 
sufficiently strong, throws the entire elastic apparatus of the 
basilar membranes with all its organs into a strong initial 
movement, which then dies away in every single part in its 
peculiar period of vibration. Thus all the nerves of the 
cochlea are excited, and thereby the perception of the noise 
is effedted without the decided prominence of any given sound. 
If the pressure of the wave of air upon the drum is prolonged 
the special vibrations of those parts of the basilar membrane 
which oscillate more rapidly than the duration of the pres- 
sure are enfeebled or suppressed, whilst those which vibrate 
more slowly are intensified. These parts of the basilar 
membrane give rise to the impression of a certain pitch of 
sound which is mixed with the noise. Still more distindtly 
is a certain pitch of sound manifested in a noise when the 
aerial pressure varies several times in succession from posi- 
tive to negative. Thus we may have all the intermediate 
stages between noises without any definite pitch and sounds 
with a pitch. Professor von Helmholtz considers this a 
proof of Exner’s theory that such noises are perceived with 
the same parts of the ear which serve for the distinction of 
sounds. 
Setting out from these considerations, Ernest Briicke has 
recently published in the “ Transactions of the Vienna 
