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,! 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. 
