18(3 



We must also consider that the farther back we go the nearer we 

 must come to a common race of man, supposing the theory of the 

 essential unity of his origin to be true, while I think the probable 

 effect of the Ice-period upon climate and the present development 

 of man, has not been hitherto sufficiently considered. The entire 

 environment must be taken into consideration, however complex it 

 is and at whatsoever cost to us the knowledge of it is to be attained, 

 before we can grasp tbe true picture of the succession of events 

 which have resulted in man as we now find him on the different 

 lands of the globe. "With the thinking minds of our race, the 

 question of the origin of man is the question of the century. 



