SOMETHING NEW ABOUT THE EAR. 167 



these, the first is the cochlea (fig. 34, coc.), which .re- 

 sembles the shell of the snail somewhat in appear- 

 ance ; while the second is constituted by three curious 

 semicircular canals (S C). Inside the cochlea is a very 

 wonderful structure, called, after its discoverer, the 

 organ of Corti. This is really a microscopical sound- 

 ing-board, or something more complex still. It con- 

 sists of about 4000 minute rods or arches, which are 

 graduated in length and height as we pass from the 

 top to the bottom of the snail-shell. Each arch or 

 rod vibrates in unison with a particular sound-wave, 

 and from their action we are supposed to gain notions 

 of tone. Helmholtz tells us that the rods of Corti 

 correspond to the seven octaves which are in common 

 use ; and this fact, with others, seems to teach us that, 

 as a tone-indicator, the organ of Corti plays its part 

 very well by us in our appreciation of sounds and 

 their pitch. 



Of the semicircular canals of the ear and their uses 

 or duties, we have hitherto not been quite so well in- 

 formed. Of yore, it was believed that they gave us a 

 power of estimating the direction of sounds, and, until 

 lately, we had to be content with this assertion. Now, 

 however, we have come into possession- of fresh facts 

 regarding these canals and their uses, and this brief 

 recital of the anatomy of the ear and its parts has been 

 intended by me simply as an introduction to a little bit 

 of tolerably recent science or rather of scientific dis- 

 covery now elevated into the rank of accepted fact. As 

 early as 1824, Flourens, the great physiologist, in ex- 

 perimenting upon these canals which, by the way, are 

 placed in three planes at right angles to one another 

 suggested that they might prove to be the organs of 

 a sense of novel and hitherto unknown nature ; and 



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