594 SCIENCE PROGRESS 



has been shown recently that many of the elements that com- 

 pose the organ of Corti are more firmly united than was 

 supposed, too firmly to be capable of any individual movement ! ; 

 finally it has been pointed out that in the pig parts of the sense 

 organ, apparently fully formed and functional, rest upon bone 

 and not upon the basilar membrane at all. 2 



All explanations of the working of the cochlea are so purely 

 a matter of speculation that it is necessarily difficult to prove 

 whether this or that objection is fatal to the Helmholtz or any 

 other theory. 



Of course if a physicist can show that a membrane of the 

 size and thickness of the basilar membrane cannot possibly 

 vibrate in sympathy to musical tones there is an end of the 

 matter so far as it is concerned. 



But short of this, the other objections just mentioned, 

 although matters for serious consideration, do not seem to be 

 necessarily fatal. 



By a modification of the Helmholtz theory, Dr. Gray 3 

 shows very conclusively that for the basilar membrane to act 

 as a resonant analyser, it is not by any means necessary that 

 single or even small groups of cords should alone vibrate for 

 each perceptible note. 



On the contrary every note would produce sympathetic 

 vibration in a more or less extensive area of the basilar 

 membrane ; but in this area the part most accurately in tune 

 with the particular note would be in maximum vibration and 

 would give to the whole stimulation the colour of that par- 

 ticular note. 



Although we may say, I think, that the Helmholtz theory 

 or some variant of it still holds the field as the orthodox ex- 

 planation of the action of the cochlea, an alternative resonance 

 theory, based on the structure of the tectorial membrane, has 

 recently been revived. 



Prompted by the structural difficulties to the Helmholtz 

 theory that have just been mentioned, certain anatomists 4 in 

 Japan and America insist that the tectorial membrane by its 



1 Hardesty, Am. Jour. Anat. 8, 1908, p. 157. 



2 Shambaugh, Am. Jour. Anat. 7, 1907, p. 247. 



3 Gray, Jour. Anat. and Physiol. 34, 1900, p. 324. 



4 Kishi, Arch.ges. Physiol. 116, 1907, p. 112 ; Shambaugh, Am. Jour. Anat. 7, 

 1907, p. 245 ; Hardesty, A?n.Jour. Anat. 8, 1908, p. 109. 



