160 THE WHENCE AND THE WHITHER OF MAN 



word to define, and our views concerning it may 

 differ. 



One thing, however, seems to me clear and evident. 

 If each successive stage in the ascending series is 

 selected or survives on account of its conformity to 

 environment there must be some element or power, 

 something or somewhat in environment specially cor- 

 responding in some way to, or suited to drawing out, 

 the characteristic of this ascending stage on account 

 of which it survives. The forces and elements of en- 

 vironment make and work against those at each stage 

 who wander from the right path, and for those who 

 follow it. And thus natural selection arises as the 

 total result of the combined working of all these forces. 

 They all unite in one resultant working along a certain 

 line, and natural selection is the effect of this result- 

 ant. In the stage represented by hydra the forces of 

 environment combine in a resultant which works for 

 digestion and reproduction and the best development 

 of their organs. But as the animal changes he comes 

 into a new relation or occupies a new position in re- 

 spect to these forces. New elements in the old envi- 

 ronment are beginning to press upon him. And the 

 resultant changes accordingly. He may be compared 

 to a steamer at sea which raises a sail. The wind has 

 been blowing for hours, but the sail gives it a new hold 

 on the ship. Steam and wind now combine in a new 

 resultant of forces. From worms upward environ- 

 ment manifests itself through natural selection as a 

 power working for muscular force and brute strength 

 or activity. 



But soon natural selection ceases to select on the 

 ground of brute force. After a time environment 



