ACTION OF THE TECTORIAL MEMBRANE 493 



when wet and immersed. It could not be obtained thick enough 

 to at all represent the thickness of the tectorial membrane. 

 Some results were obtained in using a strip of chamois skin, one 

 edge of which was turned over to represent the varying width 

 of the outspanning zone of the membrane and stitched down 

 along a line corresponding to the line of the edge of Buschke's 

 teeth, while the remaining width of the strip represented the thin, 

 attached axial zone. The long, tapering sac formed by the turned 

 edge was then filled with a melted 8 per cent solution of gelatin, 

 allowed to set, then fixed in 10 per cent formalin. When 

 immersed, in water this appeared some heavier than was de- 

 sired but when tacked down by its thin edge along upon that 

 part which represented the vestibular lip and arranged under 

 water in the adjusted model, it gave considerable evidence of 

 vibratory activity. However, after the prolonged soaking nec- 

 essary to remove the formaldehyde, this contrivance began to 

 show inequalities from beginning disintegration of the gelatin 

 after some time in the water in the model. It of course at no 

 time could be allowed to dry out. Such final results as were 

 obtained came with the use of an imitation but little more satis- 

 factory than the preceding, except that it was more permanent. 

 At a harness factory I found a piece of very thick leather which 

 was said to be elk's hide. It was so tanned as to somewhat 

 resemble the result obtained in chamois skin, being soft and 

 easily wet, and more than usually flexible when wet. Any 

 thick leather tanned by the same process would do as well 

 probably, though there is apparent reason for the impression 

 that the hides of the deer family are more porous than the beef 

 hides. ^The strip of elk's hide was cut the length and width 

 required and trimmed from the 'flesh side' to the approximate 

 relative proportions of the tectoria' membrane. It was kept 

 in frequently changed water for several days to remove any 

 substances- soluble in water. During this washing it was often 

 kneaded to increase its flexibility. Figure 5, C, gives an idea 

 of it as tacked down by its thin edge (attached axial zone) along 

 upon the vestibular lip of the spiral limbus. In this figure, 

 drawn in larger scale than the model below, it is shown, to sug- 



THB AMERICAN JOURNAL OP ANATOMY, VOL. 18, NO. 3 



