126 THE EVOLUTION THEOKY 



let us say plus — niei't t(ii;othoi-, the plus-variatii)n of A' must hv all tho 

 moiv sharply emphasized in the child. 



Thus, although the individual deteruiinants A' may not he incitinl 

 to i'ui'ther \ ai'iation by their co-operation with others \aryiu<;- in the 

 same direction, the collective ettect ol' tlu' plus-determinants will he 

 <;reater, and adherence to the same direction of variation in the 

 following oeneratiou will he assured, for if in the nerm-plasni of the 

 parent there he, for instance, sixtet'u out of twenty determinants 

 possessing the plus-variation, a minus-majority can no longer result 

 from reducing division. 



it is upon this that the operation of natural selection, that is, 

 personal selection, nuist depeud^that the gern\-plasms in which tlu- 

 favourable variation-direetion is in tlie majority are selected for 

 breeding, for it is this and nothing else that natural selection does 

 when it selects the individuals which possess the prt'ferred variations. 

 The ascending process is thus considerably advanced, because the 

 opposing determinants are niore and more eliminated tVom the germ- 

 plasm, till the preferred variations of A' are left, and among these, as 

 ascent in the direction begun continues, the opposing \ariations are 

 again set aside by germinal selection, and so on. Ivedncing di\ isions 

 and amphimixis are thus powerful factors in furthering the trans- 

 formations of the forms of life, although they are not the ultimate 

 causes of these. 



Now that we have nuxde oursehes familiar with tlu- idea of 

 germinal selection wc shall attempt to gain clearness as to what it can 

 do, and 1k)w far tho sphere of its intinence extends, and, in particular, 

 whether it can etlect lasting transformations of species without the 

 co-operation oi ]iersonal selection, and what kind of variations we may 

 ascribe to it alone. 



First, I must return foi- a moment to the question we ha\e 

 already briefly discussed — whether the variation of a determinant 

 upwards or downwards must so continue without limit. Wo might 

 be inclined to think that the great eonstaney which many speeies 

 exhibit was a plain contradiction of this, for if e\ery minute variation 

 of a determinant necessarily persisted witho\it limit in the same 

 direction, we should eK]H'ct to find all tlu^ parts of the organism in 

 a state of continual unrest, some \arying upwards, some downwards, 

 always ready to break the tyjie of the species. Must there not be 

 some internal self-regulation of the germ-plasm which makes it 

 impossible that every xariation which crops up can persist unlimit- 

 edly ? Must ihvw. not be some kind of automatic control on the part 

 of the germ-plasm, which is always stri\ ing to re-establish the state 



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