INTERNAL CAUSES OF VARIATION 205 



This theory of Elmer's is put forth as a protest and a counter 

 proposition to the theory of Darwin, afterward very much 

 elaborated and extended by Weismann and others, which was 

 to the effect that all evolution is the result of heterogeneous 

 growth trimmed down and shaped up by the extinction of indi- 

 viduals possessing unfavorable characters. The natural assump- 

 tion of the extreme selectionists is that utility is the basis of 

 all selection, and that only useful characters will be preserved, 

 the inevitable corollary of which is that all existing characters 

 are useful. 



Now the necessary consequence of selection is that after a 

 time all existing forms and characters will come to " fit " or agree 

 with the conditions of life, which are the natural agents of selection. 

 This "fit " is so accurate as to deceive many observers and lead 

 them to declare selection to be a fundamental cause of variation. 



Eimer points out two facts 1 : first, that there can be no selec- 

 tion until a choice is presented, therefore that the selective 

 process follows and does not precede the origin of a deviation ; 

 that selection may and does cause the race to vary, but that it 

 has nothing to do with the presentation of the variation in the 

 first individual, a position in which he is certainly correct. 



He argues, second, that it is not true that all characters are 

 useful, but that many species endure those that are inconvenient 

 and unfortunate, yet not sufficiently detrimental to be fatal, else 

 the line would become extinct and no such instances would ever 

 be seen. 



His position is that, first of all, " organisms develop in definite 

 directions without the least regard for utility, through purely 

 physiological causes, and as the result of organic growth'' 2 



Then, after all the characters have developed together, they 

 are passed upon by natural selection in the struggle for existence, 

 this process blotting out only those sufficiently detrimental to 

 unfit the individuals so afflicted for continuing the struggle in 

 competition with more favored forms. Selection does not remove 

 a handicap, or relieve a race from all undesirable characters. 

 It eliminates only the worst, and down to a level sufficient to 

 establish a kind of "equilibrium of life." 



1 Eimer, Organic Evolution, sects, ii and iii. 2 Eimer, On Orthogenesis, p. 2. 



