LIFE THE TRAVELER 



would have to be in every one thousand years to 

 bring it about in geologic or biologic time? 



Where does such an estimate leave natural selec- 

 tion? Of what survival advantage to the eohippus 

 could the gain of an inch in height in forty thou- 

 sand years, or of one pound of weight in four hun- 

 dred years, amount to? Such an application of 

 mathematics to the problems of evolution leaves 

 us with the conviction that there is something else 

 at work besides natural selection. Could natural 

 selection work on a capital of a gain of the one one- 

 hundredth of an inch in height in four hundred 

 years? — assuming, of course, that the gain was 

 uniform. Must there not have been an inherent 

 tendency to increase in size and to all the various 

 modifications — a primal push, as Bergson urges? 

 With man it has, no doubt, been the same. His 

 evolution has been so infinitely slow, that the me- 

 chanical conception of it is utterly inadequate. It 

 is very certain that his line of descent in Miocene 

 times was through a small animal form probably 

 no larger than a new-born baby. 



Or take the case of the elephant. These forms 

 changed and enlarged under the discipline of their 

 environment, the augmenting force or impulse 

 within always meeting and filling the changing 

 needs from without. The size of the channel of the 

 stream kept pace with the increasing size of the 

 stream. The stream branches or divides when some 



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