192 NATURAL THEOLOGY. 



The larynx, or rather the whole windpipe taken 

 together, (for the larynx is only the upper part of 

 the windpipe,) besides its other uses, is also a 

 musical instrument — that is to say, it '\^ mechanism 

 expressly adapted to the modulation of sound ; 

 for it has been found upon trial, that, by relaxing 

 or tightening the tendinous bands at the extre- 

 mity of the wind-pipe, and blowing in at the other 

 end, all the cries and notes might be produced of 

 which the living animal was capable. It can be 

 sounded just as a pipe or flute is sounded. 



upon to fill a volume. But considering the object of this work, 

 we ought not to omit the occasion of observing the union of a 

 property of life with the most complex mechanical structure im- 

 aginable. We have seen, in former notes, that for the grand and 

 vital purpose of decarbonizing the blood, the atmospheric air must 

 be drawn deep into the lungs ; and the problem is, to permit the 

 vital air to pass, and yet prevent foreign matter from finding ac- 

 cess. On this subject there is a note in the Appendix. But the 

 more remarkable circumstance in connexion with the statement 

 in the text is, that the whole of this apparatus for respiration is 

 taken from the governance of the will, and placed under a power 

 more constantly vigilant and more absolutely peremptory. The 

 sensibility about the glottis holds in control a hundred muscles ; 

 and while it excites the action, directs the force of the stream of 

 expired air with extraordinary exactness to the very point where 

 the irritating matter lodges, be it in the passages of the throat, oi* 

 in the cavities of the nose. There are many instances of the 

 same kind in the economy of the frame, where actions are ex- 

 cited by sensibilities seated in certain spots, some of them attend- 

 ed with suffering, by which our voluntary efforts are brought in 

 aid, and others where there is neither sensation nor volition, and 

 yet the muscles are controlled and regulated, and the offices per- 

 formed, witli undeviating precision. 



