81 



something which is the cause of irrita- 

 bility. 



Concerning the first of these suppo* 

 sitions, that muscles may hare a per- 

 ceptibility of injury, distinct from that 

 which we understand to be feeling, I 

 have to observe, that we can have no 

 idea of sensation but what results from 

 our own experience, which may be de- 

 fined to be perception attended with con- 

 sciousness; which kind of sensation is 

 confined to the brain alone. Of any other 

 kind of perception, it is evident we can 



never form any idea. 



. 



If a man's leg be amputated, and by 

 voltaic electricity I excite contraction in 

 its muscles for some hours, how can I 

 know whether they feel or not? We na- 

 turally judge of other subjects from our- 

 selves, and knowing that we shrink from 



G 



