PREFACE. 



Travelers tell us that monkeys will watch men around a camp 

 fire, and that as soon as the men leave, the monkeys will occupy 

 their places, warming themselves till the fire goes out. The mon- 

 keys can appreciate the warmth coming from the fire, but they do 

 not know enough to keep it up by piling on more wood. Much 

 less do they know how to start a fire when they want it. 



If we should assume these monkeys sitting around a fire and 

 engaged in evolving a theory of combustion, we would have a par- 

 allel to those biologists who are engaged in trying to give us a 

 chemical formula for heredity without having the least idea of 

 how to manipulate the forces of evolution so as to originate any 

 desired line of development, or to maintain it for succeeding gener- 

 ations when the advantageous variation has been originated by 

 accident. Knowledge that carbon unites with oxygen in certain 

 definite proportions during combustion is both interesting and use- 

 ful, but its usefulness is secondary to the usefulness of knowing 

 how to build a fire when wanted, and to maintain and control it 

 when it is built. 



Selection has been an instrument by which breeders have, in 

 a few generations, vastly improved our domestic animals, but con- 

 fessedly selection, as applied to the lower animals, is not applicable 

 to civilized man. In the preparation of the following pages it has 

 been my object to provide a simple and practical process of light- 

 ing and controlling the fires of evolution, particularly in their appli- 

 cation to man. The evolution of man is essentially the evolution 



