The Nature of the Tectorial Membrane 157 



shown in Fig. 11, they appear between the bundles, in a belt near the 

 beginning of the spiral ligament in the outer edge, and, in the inner edge, 

 the nuclei of the labium tympanicum encroach but little further than 

 the foramina nervosa of the habenula perforata. The membrane no 

 doubt grows at the edges, and the midregion being oldest, its cells are 

 probably exhausted. 



(5) The resonance theory, with its assumption of individual fibers in 

 the basilar membrane, as mentioned above, carries with it the idea that 

 the different elements of the organ of Corti, including the arches, or 

 pairs of rods of Corti, must be capable of moving separately. Not only 

 do anatomists agree that the neuro-epithelium forms a continuous mem- 

 brane throughout the cochlea, but the component cells of the organ of 

 Corti are easily seen to be intertwined and interwedged among them- 

 selves. Further, the rods of Corti's organ are probably more firmly 

 adherent to each other in their series than are any other elements of 

 the organ. This may certainly be said of the series of outer rods. In 

 teasing the cochlea for the tectorial membrane, I found in several prepa- 

 rations when mounted, considerable extents of the outer rods adhering 

 to each other, appearing on the flat as a grill-work, and wholly free 

 from other elements of the organ. From one specimen, fixed and decal- 

 cified with Perenyi's fluid, which has a macerating effect upon tissues 

 unless followed by washing in alcohol, I succeeded in obtaining a tier 

 of the outer rods more than 5 mm, long and so firmly coherent that it 

 floated about in the teasing fluid and withstood manipulation sufficient 

 to mount it entire. Occasionally short tiers were found in the mounts 

 of the tectorial membrane, sometimes adhering to its edge and lying 

 out flat and otherwise free so as to be easily studied. Fig. 12 repre- 

 sents an end of one of the latter, and was chosen because it had been 

 torn from the series in such a way that it afforded an excellent illustra- 

 tion of the shape, interrelations and character of the outer rods. This 

 preparation was fixed in Zenker's fluid. The inner rods are manifestly 

 not so resistent as the outer, for, while distorted scraps and fragments 

 from their dissolution were found in the mounts, tiers of them alone were 

 never found intact. The ends of the phalanges of the outer rods often 

 showed frayed bits of the phalanges of the inner adhering to them. All 

 appearances indicated, however, that the rods of Corti, both inner and 

 outer, must be quite firmly coherent both the inner to the outer and to 

 each other in their series. 



(6) The resonance theory applied, as it has been from the beginning, 

 to the basilar membrane, requires not only that the rods (and the other 



