372 DARWINISM AND THE PROBLEMS OF LIFE 



biogens that compose the determinant. Irregularity in 

 the nourishment of the biogens of a determinant would 

 alter their quality. But why does the unequal growth 

 of the biogens, owing to irregularities of nutrition, never 

 disturb the harmony in the determinant, as is the case 

 with panmixis ? In fact, the harmony of the parts 

 should be far more profoundly disturbed in the deter- 

 minants than in degenerating organs. In the latter 

 case the controlling influence of natural selection never 

 entirely ceases, while irregularities in the food-supply of 

 the determinants can never be controlled by natural 

 selection, as they only give occasion to selection to come 

 into play when they give rise to variations : in other 

 words, they always precede selection. Hence when we 

 see, for instance, that the determinants of a bird's feather 

 are almost never modified in such a way as to produce 

 scales or other malformations instead of a feather, we 

 must assume that there is a purposive force in the 

 determinants also that ensures the harmony of the 

 biogens. 



But our task is not completed when we reject the 

 teleological auxiliary theories from natural selection in 

 order to have a purely mechanical principle. Teleolo- 

 gical phrases and terms are only too easily slipped into 

 the theory of selection itself. In fact, we ourselves 

 have not been quite exact in our expressions in the 

 nine preceding chapters. We had to do this so as not 

 to confuse the reader by using unfamiliar phrases. The 

 teleological always comes more naturally to us than 



