SEC. 4. ON AUDITORY PERCEPTIONS AND 

 JUDGMENTS. 



632. In spite of the many and striking differences between 

 the two senses, it is possible to draw several parallels between 

 auditory and visual sensations. When we are the subject of a 

 visual sensation we refer the cause not to changes taking place 

 in the retina, but to some luminous object in the external world. 

 So also, when we are the subject of an auditory sensation we re- 

 fer the cause not to changes taking place in the internal ear, but 

 to some sounding body outside the ear and in the vast majority 

 of cases to some sounding body outside ourselves. We do not 

 simply feel auditory sensations, we perceive sounds, cf. 581. 



We have seen that in the case of the eye, visual sensations, 

 excited by events taking place in the visual apparatus itself, 

 may be confounded with sensations excited by objects in the 

 external world, and much the same happens with the ear also. 

 The tympanic membrane for instance may be thrown into vibra- 

 tions not by waves of sound, but by objects coming mechanically 

 into contact with it; particles of the dried secretion of the ex- 

 ternal auditory passage, the 'wax of the ear,' playing on the 

 tympanic membrane, may give rise to auditory sensations, a 

 4 buzzing ' or c singing in the ears,' which we cannot by the mere 

 psychological examination of the sensations themselves distin- 

 guish from auditory sensations excited in the ordinary way by 

 sonorous vibrations reaching us from some sounding body at a 

 distance. And in a general way, we may speak of entotic phe- 

 nomena, corresponding to the entoptic phenomena on which we 

 dwelt ( 549) in speaking of vision. 



Auditory sensations moreover may arise, in the complete 

 quiescence of the tympanic apparatus and perilymph, as the 

 result of changes either in the auditory epithelium or in the 

 central auditory nervous apparatus. We may be subject to 

 auditory phantoms or hallucinations, corresponding to ocular 

 phantoms or hallucinations, and like them often misleading or 

 distressing. Few persons, moreover, can listen to exciting 

 music or can hear impressive cries without experiencing "re- 

 current" auditory sensations. 



1020 



