528 STUDIES IN ADVANCED PHYSIOLOGY. 



r 



of the tympanic membrane, by others as a voluntary open- 

 ing of the Eustachian tube. 



Finally, it is of interest to reflect that the two ears are 

 as a rule attuned alike, at least so nearly alike that ordi- 

 narily we perceive a note in unison. It not infrequently 

 happens, however, that there is such a difference in the two 

 ears as to lead to the perception of the same sound at 

 different pitches, a pathological condition which when ag- 

 gravated leads to the most serious results in the apprecia- 

 tion of tones. No less remarkable than the complete 

 harmony of the two ears is the continuance of such har- 

 mony through all the vicissitudes of a person's life. Few 

 are the instruments, indeed, which do not need repeated at- 

 tention in order to hold them at their proper pitches. In 

 the basilar membrane of the ear, however, this attunement 

 seems not only one of remarkable operation to begin with, 

 but practically never requires a secondary interference. Its 

 superiority to all forms of artificial musical instruments in 

 the number of notes which it is able to perceive, in the ex- 

 actness with which it catches and reproduces all the varied 

 forms of the sounds which reach it, and in the accuracy 

 with which it remains in perfect attunement, may well 

 awaken our wonder and admiration. 



