RELATIONSHIP OF SPECIES. 253 



have gone through any such evolution as that portrayed above ; 

 I use them because they seem very aptly to illustrate a process 

 which is not perhaps an impossibility in evolution, and that in 

 some such manner as this it is perhaps permissible to look for 

 the rather baffling discrepancies that arise in estimating near- 

 ness of relationship, and which hypothesis may be suggested by 

 such possibilities as those of independent evolution. 



There is a tendency to bring forward the discoveries of Mendel 

 as refuting those of Darwin. I do not see any reason for this. 

 One argument (against the latter) appears to be that, while the 

 theory of Natural Selection accounts for the acceptance of the 

 most adaptive form, there is no conceptive building-up principle 

 or resultant in this to account for the new forms being brought 

 into being. Darwin, however, definitely states that the external 

 conditions affect the germ-cells slightly and affect their hereditary 

 potentialities : this very feasible and likely supposition thus 

 clearly producing variations, even if there were no Natural 

 Selection to single out the best, consolidate and mould them. 



This view of the case is very clearly put by Professor 

 MacBride, who points out * that Mendel himself refused to 

 investigate those characters which were of a "more or less " 

 description. 



It would appear, however, that while Mendel's work consisted 

 in showing how two different races with different characteristics 

 may, when crossed, transmit these qualities in different ratios, 

 and how even new true breeding species or forms might be 

 evolved by crossing these forms, certain followers of Mendel 

 assert that these forms demonstrate the evolution of species. 

 This, as Professor MacBride states, " brings us up against a 

 blank wall"; as very evidently these cross races must be evolved 

 from two already evoluted races. 



There may be, of course, some examples of a new united 

 race forming in nature as in artificial types, such as wheat (but 

 then it must be from already evoluted types), but one may be 

 excused if one imagines these instances to be rare, at least in 

 the higher forms. 



It would seem that the new species of this description are 



* ' Zoology, the Study of Animal Life,' pp. 69-72. 



