﻿Vol. 66,] ANNIVERSARY ADDRESS OF THE PRESIDENT. lxxxiU 



arboreal life are all in favour of a climbing habit, for which conse- 

 quently their limbs have become better adapted than for walking. 



It would be very strange, however, if some ancestral members of 

 this intelligent group had not endeavoured to escape the pressure of 

 the environment by invading the plains or open country. 8uch a 

 change of habitat would almost inevitably necessitate either the 

 assumption of an erect attitude or a return to a more perfectly 

 quadrupedal state. In the case of the baboons, who have exchanged 

 the shelter of the woods for rocky fastnesses, the latter alternative 

 has been accepted. That it was otherwise in the case of Man must 

 be owing to some special reason, most likely because he had already 

 begun to make important use of his hands. The erect attitude 

 emancipated the hands from the service of locomotion, and thus 

 afforded them full opportunity for the exercise of higher func- 

 tions. It was not, in all probability, that the erect attitude was 

 first acquired as a necessary preliminary, but that an increasing 

 appreciation of the powers of the hand led to a more frequent 

 adoption of that attitude, and thus the transformation of both 

 organs probably proceeded pari passu. 



The accomplishment of these transformations must have been 

 accompanied by correlative changes in the structure of the brain ; 

 the motor-centres for the hand in particular would be called upon 

 to respond to the various and coordinated movements which this 

 organ now learnt to perform. 



It would seem probable that ancestral Man at a very early stage 

 of his development was a social animal ; the gibbons are semi-social, 

 congregating towards evening upon the open ground in small troops ; 

 the gorilla, though less social, leads a family life and behaves like a 

 gallant gentleman in protecting his harem and offspring; he is said 

 to stand with his back against the tree in which they lodge, keeping 

 guard the whole night through; and among the lower apes the 

 baboons are famous for their rudely organized societies with 

 patriarchal leaders and appointed sentinels. 



The social instinct has, no doubt, played an immense part in 

 human evolution ; but that we must not overestimate it is sug- 

 gested by comparison of the social dog with the individualistic cat, 

 or the baboons with the less social apes. No yawning chasm 

 separates the intellectual powers of these opposed examples. Its 

 importance in the case of Man seems to lie in the fact that it 

 provided favourable conditions for the evolution of speech. How 

 this was acquired will probably always remain a matter of pure 

 speculation ; prophetic symptoms may be recognized here and there 



