30 ON THE SUCCESSION OF 



change of tension, was attempted to be supplied by strain- 

 ing the muscles of the outward ear. " The external ear," 

 we are told, " had acquired a distinct motion upward and 

 backward, which was observable whenever the patient 

 listened to any thing which he did not distinctly hear ; 

 when he was addressed in a whisper, the ear was seen im- 

 mediately to move ; when the tone of voice was louder, 

 it then remained altogether motionless." 



It appears probable from both these cases, that a collate- 

 ral, if not principal, use of the membrane, is to cover and 

 protect the barrel of the ear which lies behind it Both 

 the patients suffered from cold ; one, " a great increase of 

 deafness from catching cold :" the other, " very considera- 

 ble pain from exposure to a stream of cold air." Bad ef- 

 fects therefore followed from this cavity being left open to 

 the external air ; yet had the Author of nature shut it up by 

 any other cover, than what was capable, by its texture, of 

 receiving vibrations from sound, and, by its connexion 

 with interior parts, of transmitting those vibrations to 

 the brain, the use of the organ, so far as we can judge, 

 must have been entirely obstructed. 



CHAP. IV. 



OF THE SUCCESSION OF PLANTS AND ANIMxiLS. 



The generation of the animal no more accounts for the 

 contrivance of the eye or ear, than, upon the supposition 

 stated in a preceding chapter, the production of a watch 

 by the motion and mechanism of a former watch, would 

 account for the skill and intention evidenced in the watch 

 so produced ; than it would account for the disposition of 

 the wheels, the catching of their teeth, tiie relation of the 

 several parts of the works to one another and to their com- 

 mon end, for the suitableness of their forms and places to 

 their offices, for their connection, their operation, and the 

 useful result of that operation. I do insist most strenu- 

 ously upon the correctness of this comparison ; that it 

 holds as to every mode of specific propagation ; and that 

 whatever was true of the watch, under the hypothesis 

 above mentioned, is true of plants and animals. 



I. To begin with the fructification of plants. Can it be 

 doubted but that the seed contains a particular organiza- 



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