334 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. 



relative displacement of parts) of the fluid. It is sufficient 

 to state that such is the effect of viscidity, and that it will 

 rapidly arrest such vortices as would be formed when the 

 Reissnerian wave reaches the base of the cochlea. 



The effect of the spiral coiling of the cochlear canals 

 will be to concentrate the disturbance in the outer part of 

 each turn of the spiral. The large, longer waves will thus 

 involve a disturbance of a larger mass of fluid at each 

 level, while the smaller ones will involve movements more 

 narrowly restricted to the outer region of the canals that 

 is, to the region where the membranes are placed. 



The effects of these waves on the organ of Corti have 

 now to be considered, and the effect of the passage of a 

 single such wave as has been described will be seen to be 

 nil, or rather that it will consist only in a bodily movement 

 of the whole organ in each region first down then up and 

 then down again, with little or no relative movement of 

 the parts of the organ among themselves. 



The upper surface of the hair-cells is covered by the 

 comparatively stiff and tough reticular membrane connected 

 with the phalangar processes of the rods of Corti, and the 

 whole covering so formed is rigidly connected with the 

 basilar membrane by the stout rods of Corti and the less 

 stout, but still stiff " cuticular rods" of the cells of 

 Deiters. This skeleton, as it may properly be called, 

 insures the movement of the basilar membrane and the 

 whole mass of hair-cells and cells of Deiters as one piece 

 without deformation or relative movement of its parts. 

 The whole organ in fact in each transverse area may be 

 regarded as part of the basilar membrane, moving up and 

 down but retaining its form. 



The tectorial membrane, however, lies upon this and is 

 connected with it only at its edges. It is often described 

 as being free at its outer edge, but this edge always 



