OPENING ADDRESS. 5 



another ; that is the vast field which waits for systematic 

 investigation. Until that inquiry is made, ought we not 

 to regard the present evidence upon these intensely 

 interesting questions as incomplete ? Yet a great deal 

 of Biological Study is devoted to the examination of 

 structure solely with the view of attempting to support or 

 repudiate speculative hypotheses which hover round the 

 great central truth of Evolution. 



I do not propose to-night to refer again to this very wide 

 subject, both because of my incompetence to do so ade- 

 quately and because I wish to limit my range to subject 

 matter which involves more direct issues. I pass on 

 therefore to consider to what extent structure is a guide 

 to function. 



First class of instances, inferring Function from 

 Structure. 



Suppose that on dissecting one of the higher animals I 

 came upon a mass of tissue which in my opinion looked like 

 a muscle, and that on examining it carefully, not merely 

 with the naked eye, but also microscopically, I found 

 that it contained all the elements of striped or voluntary 

 muscle. Should I then be justified in stating what its 

 function was ? Having ascertained the form does that 

 tell me the character of the living activity ? I should 

 undoubtedly have very strong grounds for the inference 

 that this mass of muscle really was capable of contracting 

 in response to a stimulus, and thus moving the parts to 

 which it was attached, but I should not know it could do 

 so unless I saw it so act in the living state in response to 

 such a stimulus. Even having ascertained this, I am by 

 no means warranted in the next assumption that this 

 muscle which I have found to be supplied by nerves coming 

 from the central nervous system can respond, not merely 



