154 MR. Darwin's avork and 



cerned, man differs to no greater extent from the ani- 

 mals which are immediately below him than these do 

 from other members of the same order. Upon the 

 other hand, there is no one who estimates more highly 

 than I do the dignity of human nature, and the width 

 of the gulf in intellectual and moral matters, which lies 

 between man and the whole of the lower creation. 



But I find this very argument brought forward vehe- 

 mently by some. " You say that man has proceeded 

 from a modification of some lower animal, and you take 

 pains to prove that the structural differences which are 

 said to exist in his brain do not exist at all, and you 

 teach that all functions, intellectual, moral, and others, 

 are the expression or the result, in the long run, of 

 structures, and of the molecular forces which they 

 exert." It is quite true that I do so. 



"Well, but," I am told at once, somewhat triumph- 

 antly, " you say in the same breath that there is a great 

 moral and intellectual chasm between man and the 

 lower animals. How is this possible when you declare 

 that moral and intellectual characteristics depend on 

 structure, and yet tell us that there is no such gulf 

 between the structure of man and that of the lower 

 animals ? " 



I think that objection is based upon a misconception 

 of the real relations which exist between structure and 

 function, bet-.Teen mechanism and work. Function is 

 the expression of molecular forces and arrangements 

 no doubt ; but, does it follow from this, that variation in 

 function so depends upon variation in structure that 

 the former is always exactly proportioned to the latter ? 

 If there is no such relation, if the variation in function 



