ADDRESS. 31 



a question which, although we cannot now enter upon it, is quite as 

 interesting as the physiological one. 



With this history of a theory which, after having been for thirty 

 years disbelieved, has been reinstated by the fortunate combination of 

 methods derived from the two sciences, I will conclude. It may serve 

 to show how, thougli physiology can never become a part of natural 

 philosophy, the questions we have to deal with are cognate. Without 

 forgetting that every phenomenon has to be regarded with reference to 

 its useful purpose in the organism, the aim of the physiologist is not to 

 inquire into final causes, but to investigate processes. His question is 

 ever How, rather than Why. 



May I illustrate this by a simple, perhaps too trivial, story, which 

 derives its interest from its having been told of the childhood of one of the 

 greatest natural philosophers of the present century ? ' He was even 

 then possessed by that insatiable curiosity which is the first quality of 

 the investigator ; and it is related of him that his habitual question was 

 ' What is the go of it ? ' and if the answer was unsatisfactory, ' What is 

 the particular go of it ? ' That North Country boy became Professor 

 Clerk Maxwell. The questions he asked are those which in our various 

 ways we are all. trying to answer. 



' Zi/e of Clerk Maxnell (Campbell and Garnett), 1882, p. 28. 



