168 GENERAL DISCUSSION [ch. xiv 



19. That the needful variations will appear at all (p. 55). 



20. That natural selection can act continuously upon them 

 (p. 54). 



21. That most or all of the individuals that do not show the 

 favourable variation will be killed out (p. 54). 



22. That conditions will continue to vary in the same direc- 

 tion long enough to enable the sterility line to be passed (pp. 54, 55). 



23. That natural selection is so strenuous in its action that the 

 sterility line will be passed (p. 55). 



24. That when a species has become well started upon a 

 variation in one direction, there will not be offered to it one in 

 another direction, obviously better (pp. 55, 109). 



25. That the adoption of one variation does not interfere with 

 the adoption of another (pp. 55, 109). 



26. That when one variation has done its work, it shall be 

 followed by another of those that mark the species (p. 55). 



27. That morphological and anatomical necessities override 

 the effects of natural selection (p. 110). 



28. That economic botany is of no importance from the point 

 of view of natural selection (p. 8). 



29. That advantageous structural variations are so desirable 

 that they will commonly be followed up to a result of 100 per cent 

 (p. 114). 



30. That natural selection will produce uniformity in structure 

 of a morphological feature (pp. 55, 114, 124). 



31. That there was some reason why transitions were dropped 

 out more and more as evolution went up towards families (p. 113). 



32. That varieties are incipient species, species incipient genera. 



33. That numbers would increase greatly under selection 

 (p. 90). 



This is a very formidable list, and a mere glance will show that 

 many or even most of the assumptions still remain such, though 

 by the adoption of mutation in place of gradual variation several 

 of them have been removed. It is, therefore, clear that the 

 theory of evolution by the agency of natural selection, picking 

 out gradual improvements in adaptation, chiefly structural, is 

 still a very long way from being established, and as no evidence 

 has been found in seventy-five years to prove many or most of 

 the assumptions, one may be permitted to feel somewhat sceptical 

 of its discovery. Evolution is now thoroughly well established, 

 and whether natural selection carried it on or not is a matter of 

 indifference to it. 



