LECTURE IT. 9.5 



the organization of the brain being more 

 active or developed in different parts. I 

 need not tell you, gentlemen, that I went to 

 school a long while ago, and that what 

 I was there taught has become established 

 by repetition and habit, so that I cannot 

 readily express my meaning, without the 

 use of the old terms, cause and effect ; it 

 seems proper, therefore, to explain what I 

 wish to express by them. 



In several medical books published of 

 late, I read, that we have no knowledge of 

 cause or effect, save what results from the 

 continued observation of the priority of the 

 one, and the consequence of the other. I 

 was however taught to believe that we had 

 by enquiry attained a rational assurance of 

 the nature of cause and effect in a great 

 number of instances, and might, by a conti- 

 nuance of the same endeavour, probably 

 obtain it in others. All our knowledge is 

 derived from our perceptions, and they in- 

 form us, that if one body in motion impinges 

 on another free to move, the latter receives 

 part of the motion of the former according 



