44 LECTURE I, 



vinced that nothing can exert no force, and 

 consequently that these forces must either 

 be the attributes of the atoms which com- 

 pose an organized body, or of some subtile 

 and invisible substance superadded to, and 

 inherent in it. 



It has been said that Comparative Ana- 

 tomy contradicts Mr. Hunter's opinions 

 respecting life, for where there is no organ, 

 there is no function. If Nature did not 

 design an animal to see, no eye is con- 

 structed ; but how the want of an organ 

 can affect the general question of what life 

 may be, I am too dull-sighted to discover. 

 It will be shewn, and I think it must be 

 admitted, that life is an organ builder, as 

 well as a performer on the instruments it 

 constructs. That organization alone does 

 not produce the functions which belong to 

 life, must, I think, also be granted. A 

 man may sleep with his eyes open, and his 

 friend stand before him with a light ; yet 

 the organization of the retina does not 

 enable the sleeper to perceive the image of 

 his friend, though vividly depicted on its 



