CREATION BY EVOLUTION 



legs is identical with that seen in the leg of an ape; it is an 

 adaptation that makes it easy to press the soles of the feet 

 against opposite sides of a branch in climbing. 



The repetition of ancestral phases in life histories has been 

 compared to memory. If we learn tennis when we are 

 young and have no time to practice it until middle life we 

 shall nevertheless find that when we resume the game a 

 part of our skill comes back to us, that, in a word, we 

 remember it. So when salamanders have grown up in a 

 yellow box and have become yellowed in consequence, their 

 young "remember" the parental experience and strive to 

 turn yellow in spite of being enclosed in black boxes. The 

 tadpole represents a memory of the time when the ancestors 

 of the frog lived like fish. But all development does not 

 reflect purely ancestral experience. Just as memories become 

 blurred and sometimes confused with the lapse of time, so 

 secondary modifying factors tend to render the ancestral 

 record of development illegible. The organs of a larva are 

 used, broadly speaking, in much the same way as the ances- 

 tors used them, but the corresponding organs of an embryo 

 are not used, and so these tend to be imperfectly developed 

 and to degenerate into mere sketches of the ancestral organs. 

 Larval life, which represents ancestral habits, may become 

 excessively dangerous, and the larva, in self defence, may be 

 driven to adopt another mode of life, as when the young 

 of the May-fly learn to live in water and develop secondary 

 gills. But these secondary modifications are usually peculiar 

 in each kind of animal, and the fundamental ancestral 

 record can be deciphered only by comparing a large num- 

 ber of life histories, just as the historian extracts the truth 

 from ancient documents by stressing the points in which 

 they agree and discounting those in which they differ. 



The most direct proof of evolution is certainly afforded 



[58} 



