172 Irving Hardesty 



violent auditory stimulation (explosions, etc.), it might result from the 

 tectorial membrane being thrown by the excessive amplitude of the 

 vibrations so violently upon the auditory hairs that it becomes stuck to 

 them for a while by means of its glutinous matrix and thus would give 

 rise to continuous stimulation. Allien teased out in the fresh condition, 

 the membrane adheres to the needle point with a readiness very embar- 

 rassing to the operator, and sections often show it adhering to the hair 

 cells upon which it has evidently been crumpled by the manipulation. 



Calcareous deposits in the matrix of the membrane would not be 

 surprising, considering the developmental analogy it bears to the oto- 

 lithic membranes. If uniformly distributed, these would produce a stif- 

 fening of the membrane and a general impairment of the hearing; if 

 localized they would result in "tone islands." Calcification may be the 

 cause of some of the peculiarities of the "failing ears" of old age. 



■Hensen, '07, in his recent paper upholding the resonance theory as 

 applied to the basilar membrane, claims that the tectorial membrane, con- 

 sidered free by him, cannot be made to impinge upon the auditory hairs 

 by wave motion in the scala vestibuli, assuming that waves in this 

 canal would produce simultaneous depressions of the whole spiral lamina 

 below and thus of the hair cells, so that the usual space separating them 

 from the tectorial membrane when the cochlea is at rest would be main- 

 tained. And he thinks, therefore, that sensations of sound do not arise 

 till the wave motions have passed through the scala vestibuli and, there- 

 fore, only on their return in the scala tympani below does the resonance 

 action of the fibers of the basilar membrane force the hair cells upward 

 to impinge upon the under surface of the membrane. This |dea seems 

 to me subject to the following suggestions : 



(1) It seems probable that confusion would result from the anatom- 

 ical necessity, involved in his idea, that the two sides of his resonant 

 membrane would be subjected simultaneously to different sets of waves, 

 those passing above and those below a given point. 



(2) Or, if the basilar membrane is capable of undulating so freely 

 to the waves in the scala vestibuli, these waves would be imparted 

 through it to the endolymph in the scala tympani below, and the same 

 waves passing in the same direction in both canals would meet at the 

 helicotrema and would either be reflected there by the wall of the laby- 

 rinth and return towards the middle ear, meeting other waves traveling 

 in the opposite direction, or they would be damped out in the confusion 

 at the helicotrema. 



