( fi4 ) 



of the directly sensory cleiiioiils, also as a Rayleigh ring. We shall 

 have to try this the sooner, since in birds the pillars are absent and 

 so we cannot regard these formations as essential. If we try again 

 to find in Corti's organ an analogon of Rayleigh's movable ring, 

 and in abstracto it is always admissible to seek such an analogy, 

 we may never restrict ourselves to the arches alone. For by doing 

 this we should deny the essential meaning of analogy for the physiology 

 of hearing. 



So Hensen's cells may also be regarded as a movable Rayleigh 

 ring. They also rest with a relatively narrow foot on the fibres of 

 the membrana basilaris, near the foot of tiie piUar, when the human 

 organ of hearing is studied. They will also exert a damping and 

 loading influence on the vibrating fibres by their inertia. They will 

 also cause a relative node and be shifted laterally, in the direction 

 of the modiolus, by the vibration. But if this is the case they also 

 squeeze the sensory elements situated between them and the pillar '). 

 Beside this lateral pressure, experienced by the cells themselves, 

 it is not entirely impossible that also the hairs experience a pressure 

 which they now receive through the agency of the lamina reticularis, 

 which forms a whole with the capitula of the pillars. This pressure 

 will then press them against the membrana tectoria with a some- 

 what varying force, but which is always in the positive direction. 

 All these reasonings can be simpler for the ear of birds than for 

 that of man. The pillars are there absent and only the sensory elements 

 and the supporting cells are found. Also this whole lies laterally on 

 the fibres of the membrana basilaris and must experience a lateral 

 pressure of sound. 



The here developed concejilion, which deviates from the cui'rent 

 one, has the important advantage that it reduces hearing (o the 

 perception of a jiressure. The mechanical action of the vibration, 

 which in the old form of the theory of Hklmhot.tz-Hensen is vibra- 

 tory, intermittently positive and negative, now becomes a i)ermancnt 

 pressure of somewhat varying strength, to be sure, but at all times 

 in the same direction, always positive. Hearing becomes the exact 

 analogon of touching and all experience gathered for this latter sense 

 we may try to find again mutatis mutandis, in the i)hysiology of 

 hearing. 



Also small secondary advantages are gained by the new conception. 

 In the first i)lace the simple juxtaposition of the heads of the 



1) For points inward of llie node it can be shown in an elementary way that 

 the mass'es there present and sitnated unilalcrally, conlinually experience impulses 

 having a permanent conii)onent in the direction of the node. 



