OF THE SENSES. 359 



CHAPTER XIX. 



OF HEAEING. 



The Senses: General Remarks upon. Five Organs of Sense. Necessity of Apparatus for the 

 Appreciation of Time, Space, Pressure, Temperature, and Chemical Qualities. 



Of Hearing. General Structure of the Organ of Hearing. Physical Peculiarities of Sounds, In- 

 tensity, Time of Vibration, and Quality. The Tympanum, Cochlea, and Semicircular Canals 

 are for the Appreciation of these peculiarities. 



Structure and Functions of the Tympanum, or Measurement of Intensity. 



Structure of the Cochlea, its Spiral Lamina and Scalce. Measures the Time of Vibration. Ac- 

 complishment of Interference in the Scalce. Comparative Anatomy of the Cochlea. 



Structure of the Semicircular Canals. They estimate the Quality of Sounds. 



Comparative Anatomy of the Auditory Mechanism. Its Progress in Development. Imperfection 

 of the Doctrine of Means and Ends. 



OF THE SENSES. 



THE organs and functions which have thus far been described have 

 reference, for the most part, to the conservation of the indi- Function of 

 vidual being, maintaining its structure unimpaired, notwith- the senses - 

 standing the waste it is perpetually undergoing, or conducting its devel- 

 opment. We now enter on the consideration of a totally distinct ap- 

 paratus, the object of which is to put the individual in relation with ex- 

 ternal nature, and to which, therefore, the designation of mechanism of 

 external relation may be appropriately given. 



For the sentient being in its highest development, means must be pro- 

 vided for the perception of time, space, force, and quality. Five organs 

 This is accomplished by what are termed the organs of sense. of sense - 

 They are five in number : 1st. The organ of hearing ; 2d. That of see- 

 ing ; 3d. That of touching ; 4th. That of smelling ; 5th. That of tasting. 

 In the further description of the senses, it will be found that the ear is 

 the organ of time ; the eye that of space ; the tactile apparatus is for the 

 perception offeree ; and that the mechanism for smelling and tasting con- 

 jointly determine the chemical qualities of bodies ; that of smelling ad- 

 dressing itself to substances which are in the vaporous and gaseous state ; 

 and that of tasting, to such as are liquid or dissolved in water. 



We shall pursue the description of the senses in the order in which 

 they have been just enumerated, premising of them respect- The ear is the 

 ively that, the function of hearing being the reception of the or s an of time - 

 succession of sounds, periods of silence, musical notes, and their modu- 

 lations, together with the peculiarities of articulate speech, things which 

 are all inherently and essentially connected with the lapse of time, the 



