I 8 UNIVERSITY OF MISSOURI STUDIES 



In the preceding paragraph we studied briefly the ana- 

 tomical elements of the partition in their mutual relations. We 

 now have to get a definite idea of the 

 The physical physical properties of the partition as a 



properties of whole in its relation to the surrounding 



the partition fluid. These properties depend, of course, 



as a whole on the properties of its elements. The 



partition as a whole can certainly not be 

 regarded as perfectly rigid and unyielding to pressure. It con- 

 sists of tissues too soft to be unyielding. On the other hand, 

 we cannot possibly assume that under the influence of pres- 

 sure the partition could bulge to any large extent, for 

 this would be disastrous to the delicate end organs of the 

 nerve fibres. We could hardly make a mistake, then, in as- 

 suming that the partition can yield, but only withm very nar- 

 row limits up as well as down, even if we did not know 

 anything about the physical properties of the anatomical 

 elements. We know, however, that the basilar membrane is 

 a comparatively tough structure, probably capable of consid- 

 erable resistance. We are justified, then, in our conviction 

 that the whole partition bulges in response to pressure 

 but resists such pressure as soon as a certain rather narrow 

 limit of displacement is reached. 



Here, however, arises another question of the greatest 

 importance, which, unfortunately, cannot be answered with 

 anything approaching accuracy. This is the question as to 

 the elasticity of the partition. Of course, all the elasticity 

 the partition can possibly have must be the elasticity of the 

 basilar membrane. The basilar membrane is the only one of 

 the anatomical elements of the partition which might have 

 a tendency to restore spontaneously the whole partition to 

 its original position after the pressure causing the displace- 

 ment has ceased and before any pressure in the opposite 

 direction has had time to act towards this result. 



