NATURAL THEOLOGY. 



45 



ear (the concha) calculated, like an ear trumpet, 

 to catch and collect the pulses of which we have 



Explanation of the Plan of the Ear. — A, the tube of the ear, hav- 

 ing Httle glands to secrete the wax, and hairs standing across it 

 to exclude insects, without impeding the vibrations of the atmos- 

 phere ; B, the membrane of the tympanum drawn into the form of 

 a funnel by the attachment of the malleus; C, the chain of four 

 bones lying in the irregular cavity of the tympanum^ and commu- 

 nicating the vibrations of the membrane B to the fluid in the laby- 

 rinth ; D, Etistachian tube, which forms a communication between 

 the throat and the tympanum, so as to preserve an equilibrium of 

 the air in the cavity of the tympanum and the atmosphere ; E, F, 

 the labyrinth, consisting of a central cavity, the vestibule ; the 

 three semicircular canals, E, and the cochlea, F. 



Beginning from the left hand we have the malleus, or hammer, 

 the first of the chain of bones ; we see the long handle or process 

 which is attached to the membrane of the tympanum, and which 

 moves with the vibrations of that membrane; the other end is en- 

 larged, and has a groove upon it which is articulated with the next 



