188 ORIGIN OF NON-SEXUAL CHARACTERS 



activity, lead to irregularity in the process of 

 heredity. In any case the mere separation among 

 different individuals of factors originally inherited 

 together in one complex does not account for the 

 origin of the complex or of the factors. This is 

 somewhat the same idea as that of Bateson when he 

 states that it is easy to understand the origin of a 

 recessive character but difficult to conceive the 

 origin of a dominant. 



The point, however, which I desire most to 

 emphasise is that the investigations we have been 

 discussing are concerned with variations which have 

 no relation whatever to adaptation, and afford no 

 explanation of the evolution of adaptations. These 

 variations perform no function in the life of the 

 individual, have no relation to external conditions, 

 either in the sense of being caused by special con- 

 ditions or fitting the individual to live in special 

 conditions. A still more important fact is that they 

 do not explain the origin of metamorphosis. They 

 do not arise by a metamorphosis : in the case of the 

 rose comb of fowls the chick is not hatched with a 

 single comb which gradually changes into a rose 

 comb, but the rose comb develops directly from the 

 beginning. Mutationists and Mendelians do not 

 seem in the least to appreciate the importance of 

 metamorphosis or of development generally in con- 

 sidering the relation of the mutations or factors 

 which they study to evolution in general, because 

 they have not grasped the fact that there are two 

 kinds of characters to be explained, adaptational and 

 non-adaptational. T. H. Morgan, for example, 1 



1 A Critique of the Theory of Evolution, p. 67 (Princeton, U.S.A., and 

 London, 1916). 



