154 Evolution and Adaptation 



the union of the male and female elements in the act of 

 reproduction, yet that there is a rude degree of parallelism 

 in the results of grafting and of crossing of distinct species. 

 And we must look at the curious and complex laws govern- 

 ing the facility with which trees can be grafted on each other 

 as incidental on unknown differences in their vegetative sys- 

 tems, so I believe that the still more complex laws governing 

 the facility of first crosses are incidental on unknown dif- 

 ferences in their reproductive systems. . . . The facts by 

 no means seem to indicate that the greater or lesser difficulty 

 of either grafting or crossing various species has been a 

 special endowment ; although in the case of crossing, the 

 difficulty is as important for the endurance and stability 

 of specific forms, as in the case of grafting it is unimpor- 

 tant for their welfare." 



Weismann's Germinal Selection 



We cannot do better, in bringing this long criticism of the 

 Darwinian theory to an end, than by considering the way in 

 which Weismann has attempted in his paper on " Germinal 

 Selection " to solve one of the "patent contradictions " of the 

 selection theory. He calls attention, in doing so, to what he 

 regards as a vital weakness of the theory in the form in 

 which it was left by Darwin himself. Weismann says : — 



"The basal idea of the essay — the existence of Germinal 

 Selection — was propounded by me some time since, 1 but it is 

 here for the first time fully set forth and tentatively shown to 

 be the necessary complement of the process of selection. 

 Knowing this factor, we remove, it seems to me, the patent 

 contradiction of the assumption that the general fitness of 

 organisms, or the adaptations necessary to their existence, are 

 produced by accidental variations — a contradiction which 



1 Neue Gedanken zur Vererbungsfrage, eine Antwort an Herbert Spencer, 

 Jena, 1895. 



