84 'APPENDIX. 



finitely directed variation" from internal causes and of 

 a summation of "accidental" variations. He says: 

 "A summation of entirely accidental variations in a 

 given direction is extremely difficult," because "natural 

 selection thus always awaits its fortune at the hands 

 of accident whereby it is possible that the little good 

 thereby produced will be swept away by other accidents 

 (disadvantages of position) or obliterated in the fol- 

 lowing generations by unfortunate crossings." We 

 can, therefore, continues Emery, well conceive "how 

 many scientists look upon the whole theory of selection 

 as a fable, or else throw themselves into the arms of 

 Lamarckism." Unquestionably Emery has here 

 singled out the insufficient points in the assumption of 

 a selection of "accidental" variations ; he has recog- 

 nised the necessity of operating, not with single varia- 

 tions, but with "directions of variation." He has not, 

 however, attempted the derivation of directed ten- 

 dencies of variation from known factors ; he apparently 

 thinks of them as of something which has sprung from 

 unknown constitutional factors and consequently 

 ascribes to them the capacity of shooting beyond their 

 mark, so to speak, that is, of acting beyond and ahead 

 of utility, and so of producing modifications which may 

 lead to the destruction of the species. 



