80 



occasion merely direct your attention to 

 the consideration of one other subject, 

 which is, the opinions we may be war- 

 ranted in forming, respecting the con- 

 nection of irritability and sensibility. 

 r 



This subject has been the cause of 

 much controversy. Haller maintained 

 that irritability was a distinct property in- 

 herent in muscles ; to use his own words, 

 that they had a vis insita, independent 

 of the vis nervea; which opinion has of 

 late received additional corroboration from 

 some experiments of Mr. Brodie. Those 

 who object to this opinion, can, I think, 

 only oppose it on the following grounds. 

 They must contend either that the muscles 

 have a kind of perception of injury which 

 causes them to contract, even though 

 they are unconnected with the brain ; 

 or that ' the nerves are the organs which 

 prepare end supply the muscles with 



