CH. XI] B. MORPHOLOGICAL 117 



at one time held by almost everyone, has passed away, though 

 natural selection, which is looked upon as depending upon 

 structural adaptation, survives. 



But the great difficulty which has always hindered the selec- 

 tionist is to explain how natural selection got a grip upon the 

 early stages of any of these characters. If they were produced in 

 one operation, as differentiation demands, everything is simple, 

 but in that case it is clear that natural selection can have little 

 or nothing to do with their appearance. One must drop out 

 natural selection as a guiding cause in evolution ; it could get no 

 grip upon the evolution of these structural features by gradual 

 adaptation, and it could have nothing to do with it if they ap- 

 peared fully-fledged. This test is in full favour of differentiation 

 and what would seem the most probable order of things is that 

 evolution, strictly so-called — the appearance of continually new 

 structural forms — had little or nothing to do with adaptation of 

 those forms to the conditions bv which thev were surrounded. 

 They would inherit from the parents a reasonable probability of 

 not being too unsuitable to survive at all, and it would then be 

 "up to" natural selection gradually to fit them in minute detail 

 for some particular combination of the conditions of life that 

 existed near to the spot where they began, or to destroy them if this 

 could not be done. Natural selection, in other words, strenuous 

 though its action may be, has apparently nothing to do with the 

 evolution of plants, though it has everything to do with the way 

 in which they finally become best suited to some detail of com- 

 bination of the conditions by which they are surrounded. Evolu- 

 tion and natural selection, in other words, may be represented as 

 working more or less closely at right angles to one another, and 

 the evolution goes on by large steps, as required by the theory of 

 differentiation. 



The theory of gradual formation of the structural features of 

 plants seems to be left with little or no support, and a much 

 simpler explanation of everything is provided by that of sudden 

 appearance. People say that we have no evidence of such an 

 occurrence, but we have no evidence of gradual acquirement, and 

 a mere glance at the table of family characters in Appendix I will 

 show that a great number of them are so divergent that they 

 allow of no intermediate, and if one therefore cannot derive them 

 by stages, they must have come in one step. And this is especially 

 true when one finds that gradual adaptation will not do as a cause 

 for change. 



