1. Can we dispense with the principle of natural 255 selection?
2. Nägeli’s theory of transformation from internal 256 causes
3. A definite course of development is possible 258 without a self-changing idioplasm
4. Conclusive importance of ‘adaptations’ 260
5. The structure of whales as an example of 261 adaptation
6. Transformation takes place by the smallest steps 264
7. The foundation of such minute changes depends upon 266 individual variability
8. Difficulty in accounting for variability on the 266 supposition of a continuity of the germ-plasm
9. Previous theories by which variability has been 267 accounted for
10. Non-transmission of acquired characters 267
11. Nägeli’s and Alexis Jordan’s experiments 269
12. Germ-plasm is only altered with great difficulty 271
13. The source of individual variation lies in sexual 272 reproduction
14. The process of natural selection does not operate 274 when asexual reproduction takes place
15. Origin of variability in unicellular organisms 278
16. Sexual reproduction effects combination 279
17. E. van Beneden’s and V. Hensen’s theory of sexual 282 reproduction as a process of rejuvenescence
18. Theoretical objections to such a view 283
19. Original significance of conjugation 286
20. Preservation of sexual reproduction by means of 287 heredity
21. It is lost in parthenogenesis for reasons of 289 utility
22. Parthenogenesis prevents further transformations 290
23. It excludes Panmixia and thus prevents disused 291 organs from becoming rudimentary
24. Final considerations 294
