104 AYERS. [Vol. VI. 



thinning, which approaches the plane of the reticular mem- 

 brane. It extends scarcely beyond this membrane, but little 

 is known concerning its true external termination. On its 

 external border it is furnished with a system of quite large 

 hyaline fibres, which by anastomosing form a sort of net, which 

 for its beauty is not surpassed by the membrana reticularis and 

 which Boettcher has well represented in his figures. This net- 

 work reaches at least to the niveau of the external supporting 

 cells, but its relation to the latter is not known. These trabec- 

 ulas of the outer border are in isolated membranes of Corti, 

 usually bent inward over one or the other of its faces. Between 

 the two systems of trabeculae, internal and external, the mem- 

 brana Cortii shows in a radial course a fibrous structure, fine but 

 quite apparent. The constituent filaments, which are easily 

 isolated in preparations, are undulating and lightly interlacing. 

 The membrane tears readily in radial courses, following the 

 direction of its constituent fibrillae. 



" Does there exist between the epithelium of the sulcus spi- 

 ralis and the membrane of Corti a considerable open space .-* 

 It is impossible for me to answer this question categorically. 

 On the inferior face of this membrane one notices quite fre- 

 quently polygonal depressions, which are in all probability pro- 

 duced by cellular elements. They may also correspond to the 

 membrana reticularis." 



According to Boettcher the membrane of Corti gives off 

 branches of considerable size, which implant themselves upon 

 the plateau of the cells of Corti and of the inner auditory cells. 

 The rods carried by the cells are supposed to be remains of 

 these processes which have been broken off in the preparation 

 a little above the reticulate membrane. The description which 

 we have given of these rods or hairs, and above all their regu- 

 larity, renders, it seems to us, Boettcher's view inadmissible, at 

 least as regards the significance of the rods. 



The physical properties of the membrane of Corti merit all 

 our attention. Hensen has announced, and I have many times 

 verified the fact, that in the fresh state it is a soft substance, 

 somewhat gelatinous and almost without elasticity. It takes 

 and preserves all the shapes which one forces upon it with the 

 instruments, and it rolls up without the least resistance. If 

 we consider that such a pasty mass, as we may say, rests upon 



