ESSAY-REVIEWS 



THEORIES OP AUDITION, by Prof. E. H. Barton, D.Sc, F.R.S. : 

 on An Enquiry into the Analytical Mechanism of the Internal Ear, 



by Sir Thomas Wrightson, Bart., Memb. Inst.C.E., with an Appendix 

 on the Anatomy of the part concerned by Arthur Keith, M.D., 

 F.R.S. [Pp. xi + 254.] (London: Macmillan & Co., 1918. Price 

 12s. 6d. net.) 



This work is distinctly specialised and suggestive. It appears to be the out- 

 come of protracted thought and research, and, in addition to presenting much 

 anatomical detail, puts forward a somewhat novel theory of audition. 



The two writers concerned contribute nearly equal parts of the work. The 

 early portion, by Sir Thomas Wrightson, consists of four chapters occupying 

 155 pages with 56 figures in the text. The appendix, by Dr. Keith, covers 

 99 pages and has 27 text-figures. There are also 8 folding plates. 



Throughout the work the anatomical descriptions are very elaborate, and are 

 accompanied by large and clear diagrams, which will be welcomed by all 

 interested in the intricate complexity of the internal ear. This part of the work 

 rests upon the solid ground of observed facts. 



But to some readers the chief interest will centre in the theory of hearing 

 advanced by Sir T. Wrightson and accepted by Dr. Keith. 



The presentation of this culminates in the fourth chapter, the earlier chapters 

 being devoted to elementary matters and preliminary ideas. The authors 

 emphasise the point that whereas some have regarded the internal ear as a 

 structure they recognise it to be a mechanism. (The query here arises as to 

 whether they have sufficiently borne in mind the high frequency at which it 

 works.) But the view they hold about the action of this mechanism differs from 

 the Helmholtz theory of sympathetic resonance. Here we enter upon debatable 

 ground. The points at issue are briefly as follows : 



(a) The resonance theory regards some particular parts of a graduated 

 mechanism in the internal ear as capable of sympathetically responding to the 

 air waves of correspondingly suitable frequency falling upon the external ear. 

 The nerve fibres from these responding parts are then supposed to convey to the 

 brain the mere fact of their stimulus. Thus, the analysis of sounds (or the 

 detection of their frequencies) is accomplished in the internal ear and not in 

 the brain, which only notes which nerve-fibres are stimulated. The sensation of 

 a sound of frequency 100 per second thus corresponds to the stimulus of the 

 nerve fibres which end in those structures which respond best to vibrations of 

 about that frequency. 



(&) The view of the present authors is that when a pressure wave of the air 

 arrives at the external ear there is a nerve impulse corresponding to each crest 

 and trough of this wave, and also to each point where the graph of the wave 

 crosses the time axis. They hold that all parts of the graduated mechanism of the 



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