106 A. M. Mayer—Researches in Acoustics. 
the hair-cells will not vibrate but will only experience com- 
pressions and dilatations like the fluid in which they are 
immersed. Therefore, there appears to me a physical basis for 
the opinion that either there is no communication between the 
rotunda and moves this membrane outward. When, however, 
the — outward, the pressure is relieved from the 
elastic lar membrane, which is now moved upward, while 
the fenestra rotunda moves inward.* 
* If we could examine, at the same time, vibrating points on the stapes and on 
fenestra with a vibration-microscope, I imagine that these poi 
_ would exhibit no difference in phase when the membrana tympani vibrated to a 
