Determinate Variation i6i 



work. Admitting 'determinate evolution,' the question as 

 to the causes which 'determine' the evolution is never- 

 theless still open, and various answers have been given to 

 it. The Neo-Lamarckians say ' use-inheritance ' (as Eimer, 

 who calls the determination secured by this means 'ortho- 

 genesis'); Weismann says 'germinal selection'; those who 

 accept ' organic selection ' say that it is a determining 

 factor (the resulting determination of evolution being 

 called 'orthoplasy'); others say 'determinate variation^ 

 (continued in the same direction for successive genera- 

 tions); Professor Osborn says, 'determinate variation' 

 with 'organic selection.' Determinate variatio7i, \.\\Qn, in 

 the proper meaning of that term, is only one way of account- 

 ing for determinate evolution, and to the writer it is not 

 the true way ; at any rate, it is not necessarily involved 

 in the theory of 'organic selection.' 



Let us look more closely at ' determpate variation.' 

 Supposing that by variation we mean 'congenital varia- 

 tion,' then we may ask : When are variations determinate .? 

 When for any reason they are distributed in a way different 

 from that required by the law of probability or chance. 

 The problem of determinate variations is purely one of 

 distribution; and is to be investigated for each gener- 

 ation, quite apart from its holding for a number of succes- 

 sive generations (and so giving 'determinate evolution'). 

 Further, the possible determinateness of variation is to 

 be distinguished carefully from the extent or zvidth of 

 variation. By 'extent' of variation is meant the limits of 

 distribution of cases about their own mean ; while relative 

 determinateness means the distribution of cases, according 

 to some other law than that of probabilities, about a mean 

 established for the parents in the earlier generation. 



