CONTENTS 



PART II. 

 THE EVOLUTION OF THE REALM OP ORGANISMS. 



LECTURE XL 



PAGE 



THE CONCEPT OF EVOLUTION . 353 



1. A Question of Terms, 353 2. The Evolution of Organ- 

 isms Contrasted with Inorganic Genesis, 356 3. Organic 

 Evolution Contrasted with the History of Human Societies, 

 359 4. Definition of the Concept of Organic Evolution, 360 

 5 May Evolution Have Been a Process of Analytic Sim- 

 plifying, not of Synthetic Complexifying?, 361 6. The 

 Logical Validity of the Evolution Formula, 367 7. Diffi- 

 culties in tho Way of Concrete Evolution Theory Lead to 

 Hypotheses of Transcendental Underpinning, 370 8 In 

 What Sense Is Organic Evolution Continuous?, 373 9. In 

 What Sense Is Organic Evolution Progressive?, 375. 



LECTURE XII. 



GREAT STEPS IN ORGANIC EVOLUTION 383 



l.The Origin of Organisms upon the Earth, 383 2. The 

 Nature of the First Organisms, 387 3 Establishment of 

 Diverse Types of Cellular Organisation, 388 4. The Diver- 

 gence of Green Plants, 389 5. The Making of Bodies, 390 

 6. The Divergence of the Sexes, 391 7. Progressive Dif- 

 ferentiations and Integrations, 392 8. Rise and Progress 

 of Backboned Animals, 394 9. The Ascent of Man, 397 

 10. General Impressions of Animate Evolution, 397. 



LECTURE X1IL 



ORIGINATIVE FACTORS IN EVOLUTION: VARIATION . . 407 



1. The Central Problem of ^Etiology Is the Origin of Heri- 

 table Variations, 407 2. Variations Distinguished from 

 Modifications, 408 3. Discontinuous Variations (or Muta- 

 tions) and Continuous Variations (or Fluctuations), 410 

 4. Problem of the Origin of Variations, 415 5. Correla- 

 tion of Variations, 424 6. Theory of Temporal Variations, 

 425 7. Evidences of Definiteness in Variability, 426 8. 

 Germ-cells as Implicit Organisms, 428. 

 ill 



