The Nature of the Tectorial Membrane 111 



blue iu normal salt. Though a few fairly satisfactory bits of the 

 membrane were obtained from the methylene blue solution, the method 

 had to be early discarded as being too coarse. The action of the 

 section chisel in crashing through the bony labyrinth lacerated sorely 

 the delicate structures within, the very action of the freezing appeared 

 to result in distortion and dissociation, and positive orientation of the 

 bits of membrane obtained was impossible. 



Lightly crushing of the cochlea followed by gently teasing away the 

 parts under fluid was next resorted to. A cochlea was held upon a 

 solid surface and gently tapped around with a light hammer till the 

 bony wall was sufficiently cracked without rupturing the wall of the 

 membranous labyrinth and the whole placed in a petri-dish of amniotic 

 liquor obtained from the sacs of younger foetuses. Under the dissecting 

 microscope the bits of the crushed bone were then carefully removed 

 with fine pointed forceps, and, with the same forceps and with teasing 

 needles, the outer wall of the scala vestibuli gently torn away from as 

 nearly as possible the entire length of the cochlea. Even with the 

 greatest care, this tearing usually ruptures the vestibular (Eeissner's) 

 membrane and thus seriously disturbs the structiires below it. "With 

 practice, portions of the vestibular membrane could be removed sepa- 

 rately and the tectorial membrane identified. 



The tectorial membrane floats free from its attachment upon the 

 labium vestibulare of the spiral limbus during the disturbance necessary 

 for the removal of the structures and the consequent agitation of the 

 fl.uid in which it is immersed, but, because of the fact of its being so 

 very delicate and flexible and so extremely subject to surface tension, 

 only short pieces could be obtained (3 to 5 millimeters in lengih) 

 undistorted and free from adhering particles of bone and other debris. 

 It was found that these pieces had to be isolated and handled .by pro- 

 ducing currents in the fluid to waft them to desired positions, for upon 

 touching them they would adhere to the point of the teasing needle so 

 closely that freeing them meant distortion or destruction. These pieces 

 were stranded upon the end of a clean slide, to which they were found 

 to adhere less than to the ordinary section lifter, and some were mounted 

 directly in glycerine and in glycerine jelly. Others were washed from the 

 slide into a 0.1 per cent solution of methylene blue in normal salt and 

 let it remain in this from 30 minutes to 2 hours. With the dish of stain 

 over a white surface, these were again stranded upon the slide, rinsed 

 as quickly as possible in salt solution to remove the surplus stain, and 



