66 LECTURE II. 



In the first lecture I endeavoured to 

 show that Mr. Hunter's Theory of Life 

 was verifiablej and that it afforded thfe 

 most rational solution of the cause of irri- 

 tability, which had hitherto been offered to 

 the public. It now appears that it does 

 not essentially differ from that of the best 

 physiologists, with regard to the explan- 

 ation it affords of the nervous functions. 

 As it is impossible to review all the phse- 

 nomena of these functions in a lecture, 

 I shall on the present occasion merely 

 direct your attention to the consideration 

 of one other subject, which is, the opi- 

 nions we may be warranted in forming, 

 respecting the connection of irritability and 

 sensibility. 



This subject has been the cause of much 

 controversy. Haller maintained that irri- 

 tability was a distinct property inherent 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 expe- 

 riments of Mr. Brodie. Those who object 



