THE PRESIDENTIAL ADDRESS. 11 



what line of evidence we select to follow— evidence gathered by 

 anatomists, by embryologists, by physiologists, or by psychologists— we 

 reach the conviction that Man's brain has been evolved from that of an 

 anthropoid ape and that in the process no new structure has been intro- 

 duced and no new or strange faculty interpolated. 



In these days our knowledge of the elaborate architecture and 

 delicate machinery of the human brain makes rapid progress, but I should 

 Unexplained mislead if I suggested that finality is in sight. Far from it ; 

 Problems. our enquiries are but begun. There is so much we do not 

 yet understand. Will the day ever come when we can explain why the 

 brain of man has made such great progress while that of his cousin 

 the gorilla has fallen so far behind? Can we explain why inherited 

 ability falls to one family and not to another, or why, in the matter 

 of cerebral endowment, one race of mankind has fared so much 

 better than another ? We have as yet no explanation to offer, but 

 an observation made twenty years ago by one on whom Nature has 

 showered great gifts — a former President of this Association and the 

 doyen of British zoologists — Sir E. Ray Lankestcr — deserves quotation in 

 this connection : ' The leading feature in the development and separation 

 of Man from other animals is undoubtedly the relative enormous size of 

 the brain in Man and the corresponding increase in its activities and 

 capacity. It is a striking fact that it was not in the ancestors of Man 

 alone that this increase in the size of the brain took place at this same 

 period — the Miocene. Other great mammals of the early Tertiary period 

 were in the same case.' When primates made their first appearance 

 in geological records, they were, one and all, small-brained. We have to 

 recognise that the tendency to increase of brain, which culminated in the 

 production of the human organ, was not confined to Man's ancestry but 

 appeared in diverse branches of the Mammalian stock at a corresponding 

 period of the earth's history. 



I have spoken of Darwin as a historian. To describe events and to 



give the order of their occurrence is the easier part of a historian's task ; 



his real difficulties begin when he seeks to interpret the 



Conception happenings of history, to detect the causes which produced 



of Evolution them, and explain why one event follows as a direct sequel to- 

 illustrated. L J , .. . , il _ 



another. Up to this point we have been considering only the 



materials for Man's history, and placing them, so far as our scanty informa- 

 tion allows, in the order of their sequence, but now we have to seek out the 



