PREFACE. 



THESE ESSAYS originally appeared in the 

 columns of the ' St. James's Gazette,' and I 

 have to thank the courtesy of the Editor for 

 kind permission to republish them. My ob- 

 ject in writing them was to make the general 

 principles and methods of evolutionists a little 

 more familiar to unscientific readers. Bio- 

 logists usually deal with those underlying 

 points of structure which are most really im- 

 portant, and on which all technical discussion 

 must necessarily be based. But ordinary 

 people care little for such minute anatomical 

 and physiological details. They cannot be 

 expected to interest themselves in the flexor 



