LECTURE VI. 071 



propensity, and of exerting its powers in 

 different modes and degrees in the struc- 

 tures or substances in which it inhered. 

 He thought that a similar vital principle 

 was diffused throughout the body in differ- 

 ent degrees, and to use the expressions 

 with which his friends have furnished him, 

 that the materia vitse diffusa communicated 

 with the vital energies of the brain, by 

 means of actions transmitted through the 

 nerves or internunciate chords, as he called 

 them; he also considered these actions to 

 be productive of the sympathetic effects re- 

 ferred to in the introductory lectures, and 

 which are wholly unintelligible upon any 

 other supposition. 



In forming our opinions on the subject 

 of sensation, I admit that a choice of diffi- 

 culties is presented to us; and I prefer 

 that which seems the least. If I judge, as 

 I own is natural, of other things by myself, 

 I shall be led into a dilemma that a man 

 of great intellectual powers and acquire- 

 ments has been, and whom I have al- 

 ready praised for the important additions 

 he has made to our knowledge of the func;- 



