10 IRVING HARDESTY 



pressed axisward and pressed upon the spiral organ, and the spiral 

 organ itself is pressed down upon the spiral lamina to an extent render- 

 ing it unrecognizable for this region of the coil. Except that it is pressetl 

 down in contact with a part of the spiral organ, there is no evidence 

 whatever in this figure that the membrane is attached to the organ, 

 other than that the hairs of the hair cells, represented in the figure as 

 one simple filament from each hair cell and much longer than normal, 

 are shown continuous into the membrane. I do not think that an 

 insertion of the hairs into the tectorial membrane is ever seen in any 

 stage of development except when the membrane has been crumpled 

 or compressed upon the hairs, sticking the hairs into it. So far as I 

 know, the only recent papers which claim this insertion as a normal 

 attachment of the membrane are those of Prentiss and Shambaugh. 

 Prentiss states that in all his preparations of the older cochleae the 

 membrane was badly shrunken. To me they prove nothing as to the 

 membrane beyond its mere existence, certainly nothing for argument 

 as to an attachment of its outspanning zone. 



To those of us suffering under the misapprehension that the apex 

 of the cochlea is always directed toward the zenith, regardless of the 

 position of the head, while the sense of hearing is being exercised, Pren- 

 tiss devotes a drawing and some of his text to show that in the pig, 

 while feeding for example, the tectorial membrane may be below 

 rather than above the spiral organ and therefore, must fall away from 

 the spiral organ if not attached to it, and render the animal deaf 

 while feeding. In my teasing out of the membrane, it appeared, as 

 I stated, to possess a specific gravity but little greater than the fluid 

 in which it lies and that it manifested a transverse elasticity amph' 

 sufficient to hold it in its position spanning over and close to the spiral 

 organ, its broad axial edge alone being attached. Prentiss' dissected 

 preparations, made better than mine, no doubt showed the same 

 qualities. 



MATERIAL AND METHODS 



This study is made almost wholly upon cochleae of the adult 

 pig and pig fetuses. Some cochleae of the adult ox were used 

 for comparison and also some isolated sections of cochleae of 

 the rat and guinea-pig were referred to. A few adult human 

 cochleae were used but none could be obtained in sufficiently 

 fresh condition for other than general comparison with those 

 of the pig. 



As is well known, the structures of the cochlear duct, especially 

 the elements of the spiral organ, suffer maceration very quickly 

 after death. Pig material obtained as promptly as three hours 



