286 AYERS. [Vol. VI. 



of the dorsal edge of the membrana Reissneri. The whole of 

 the stria vascularis and the membrana Reissneri are thus easily 

 removed, leaving freely exposed the cochlear organ intact. The 

 limbus spiralis is then easily detached with needles by punctur- 

 ing along the course of Rosenberg's canal, so that the spiral 

 papilla on the basilar membrane may be transferred to slide 

 and cut into pieces more or less complete circles. The whole 

 under one cover is mounted in serum and the edges of the 

 cover glass painted with cement to hinder evaporation. The 

 microscope with this preparation is placed in a position favor- 

 able to the transmission of vibrations to the liquid, and it is then 

 seen that the fibres of the hair band vibrate under the influence 

 of tones given off by the piano or a tuning-fork. 



Our experiments were successful in showing that the hair 

 band as a whole is violently agitated by loud tones, but not con- 

 clusive as to localization of tones of different pitches in different 

 parts of the hair band. Owing to the conditions of the experi- 

 ment it could not be determined that the basilar membrane was 

 affected by the vibrations. 



When such a preparation is placed on the stage of a micro- 

 scope isolated in such a manner that sonorous undulations can 

 reach the slide surface from the air alone, we have placed the 

 hairs under conditions which severely test the delicacy of their 

 powers of responding to the slight disturbances of the atmos- 

 phere produced by musical instruments such as the piano, 

 violin, or horn. All of our experiments were performed with 

 the aid of a piano. 



The microscope was isolated by means of several cushions 

 in the middle of a room in such a way that only vibrations from 

 the piano strings affecting the air and reflected directly towards 

 the open space between slide and cover glass, which was occu- 

 pied by the organ of Corti and its supernatant fluid, could 

 noticeably affect the hairs — probably by direct transmission 

 from the air to the liquid, since undulatory and other disturb- 

 ances of the atmosphere are much more readily given up to or 

 transferred from a gas to liquids than to solids. And since the 

 thinner of the two glass plates was supported by wax feet rest- 

 ing upon the other, the motion of both would by this means be 

 more or less damped. 



The motion, at any rate, could arrive only by transfer from the 



