VI PREFACE. 



for several generations be subjected to divergent forms of selection ; 

 and in all the forms of animal life that are capable of learning by 

 experience, accommodation, controlled by the principles producing 

 habitudinal segregation, is constantly guiding and shaping racial 

 segregation. 



Though more familiar words have been chosen for the title of this 

 volume, the subject here treated would have been clearly expressed 

 if the title had read: "Habitudinal and Racial Segregation; or, the 

 origin and intensification of organic types, guided by innovation and 

 tradition acting under segregate association, and established by 

 variation and heredity acting under segregate intergeneration." 



JOHN T. GUUCK. 

 OBERUN, OHIO. 



