LECTURE XIX. 



THE CONTROL OF LIFE: LESSONS OF 



EVOLUTION. 



§ 1. The Idea of the Controllability of Life. § 2. Heredity the First 

 Determinant of Life. § 3. Nurture the Second Determinant 

 of Life. § 4. Selection the Third Determinant of Life. § 5. 

 Importance of Correlating Organismal, Functional, and En^ 

 vironmental Betterment. § 6. Dangers of False Simplicity or 

 Materialism, § 7. Science for Life. 



A STUDY of human history which yielded no practical 

 counsel to mankind would be self-condemned, and the same 

 must be true of a study of animate evolution. What are 

 the lessons of evolution? 



§ 1. The Idea of the C ontrolldbility of Life. 



There is practical suggestiveness in the very idea of or- 

 ganic evolution. Darwin changed a relatively static con- 

 ception of the Realm of Organisms into an intensely dynamic 

 one. The forms of life which seemed so fixed were shown 

 to be in racial flux — though the movement might be as im- 

 perceptible as a glacier's flow. What Man could do in a 

 relatively short time by breeding from selected variants was 

 shown by his success with domesticated animals and cul- 

 tivated plants. Thus the whole aspect of things was changed. 

 The outlook became kinetic, and this led on naturally to 

 the practical idea of ike controllability of life. If flowers 

 and pigeons and the like can be controlled, and controlled 

 so well, then why not human life also? If Man can evolve 



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