ON THE PHONOGRAPH. 



783 



i. Hair Cells. 



Base, 

 Middle, . 

 Apex, 



Base, 

 Middle, . 

 Apex, 



Length of Inner Hair Cells. 







mm. 



inch. 



1000 times 



•018 



•00072 



•72 



•024 



•00096 



■96 



•024 



•00096 



•96 



Length of Outer Hair Cells. 







•03 



•0012 



1-2 



•04 



•0016 



1-6 



•04 



•0016 



1-6 



As we pass from base to apex, both inner and outer hair cells increase in size. 



k. Length of the Hairs of the Hair Cells. 



Base, 



Middle, 



Apex, 



Base, 



Middle, 



Apex, 



Hairs of Outer Cells. 







mm. 



inch. 



1000 times 



•0045 



•00018 



•18 



•0060 



•00024 



•24 



•0080 



•00022 



•22 



Hairs of Inner Cells. 







•0045 



•00018 



•18 



•0055 



•00022 



•22 



•0055 



•00022 



•22 



(1) In both, the hairs increase in length from base to apex. 



(2) The increase is greater in the hairs of the outer cells. 



mm. 



inch. 



1000 times 



285 



•0114 



11-40 



•340 



•0136 



13-60 



345 



•0138 



13-80 



1. Radial Breadth of Memhrana Tectoria, covering Corti's Organ. 



Base, 



Middle, 



Apex, 



It increases from base to apex, like the basilar membrane, but it is not far off one-third of Hie breadth of this membrane. 



m. Comparison of Man, Cat, and Rabbit. 



Ear teeth, .... 

 Holes in Habenula for nerves, 

 Inner rods, .... 

 Outer rods, .... 

 Inner hair cells (one row), 

 Outer hair cells (several rows), 

 Fibres in basilar membrane, . 



Man. 



Cat. 



Rabbit 



2,490 



2,430 



1,550 



3,985 



2,780 



1,650 



5,590 



4,700 



2,800 



3,848 



3,300 



1,940 



3,487 



2,600 



1,600 



. 11,750 



9,900 



6,100 



. 23,750 



15,700 



10,500 



