Variability and Inheritance. 139 



Whatever increases the creature's power of vary- 

 ing increases its possibility of progressing. For it 

 is through the mysterious power of inheritance 

 combined with the power to vary, shown most 

 actively by the male, and transmitted by him to 

 his posterity, both male and female, that animals 

 finally reach that form which is best adapted to 

 their particular surroundings, and which, as life 

 evolves, is expressed in ever higher forms. 



In time of peace and plenty and freedom from 

 all hardship, most of the creatures that are born 

 will live, no matter in what way they may have 

 shown variation ; but let there come a time of 

 hardship, and those which have the best endow- 

 ment of strength, or other quality for resisting or 

 overcoming the adverse conditions, will live, and the 

 less fortunate perish. The descendants of those 

 that survive, inheriting their characteristics, will the 

 better survive, and in course of time, after many 

 weedings-out of those less capable of enduring the 

 conditions, there may be formed some particular 

 variety of creature of a distinct and definite form. 



This power of the creature to come into har- 

 mony with its surroundings depends upon two 

 things, — its ability to vary, and its ability to trans- 

 mit its new powers through inheritance. 



Variability and inheritance are the most impor- 

 tant factors of reproduction, and to these powers 

 is owing the multiform variety and beauty of life 

 on the earth. 



