100 Heredity and Variation in Modern Lights 



discovery, is not very onerous. Tlie doctrine "gw6 tout est au mieux" 

 was therefore preached with fresh vigour, and examples of that 

 illuminating principle were discovered with a facility that Pangloss 

 himself might have envied, till at last even the spectators wearied of 

 such dazzling performances. 



But in all seriousness, why should indefinite and unlimited 

 variation have been regarded as a more probable account of the 

 origin of Adaptation ? Only, I think, because the obstacle was shifted 

 one plane back, and so looked rather less prominent. The abundance 

 of Adaptation, we all grant, is an immense, almost an unsurpassable 

 difficulty in all non-Lamarckian views of Evolution ; but if the steps 

 by which that adaptation arose were fortuitous, to imagine them 

 insensible is assuredly no help. In one most important respect 

 indeed, as has often been observed, it is a multiplication of troubles. 

 For the smaller the steps, the less could Natural Selection act 

 upon theuL Definite variations — and of the occurrence of definite 

 variations in abundance we have now the most convincing proof — 

 have at least the obvious merit that they can make and often do 

 make a real difterence in the chances of life. 



There is another aspect of the Adaptation problem to which I 

 can only allude very briefly. May not our present ideas of the 

 universality and precision of Adaptation be greatly exaggerated? 

 The fit of organism to its environment is not after all so very close — 

 a proposition unwelcome perhaps, but one which could be illustrated 

 by very copious evidence. Natural Selection is stern, but she has 

 her tolerant moods. 



We have now most certain and irrefragable proof that much 

 definiteness exists in living things apart fi'om Selection, and also much 

 that may very well have been preserved and so in a sense constituted 

 by Selection. Here the matter is likely to rest. There is a passage 

 in the sixth edition of the Origin which has I think been overlooked. 

 On page 70 Darwin says " The tuft of hair on the breast of the wild 

 turkey-cock cannot be of any use, and it is doubtful whether it can 

 be ornamental in the eyes of the female bird." This tuft of hair is a 

 most definite and unusual structure, and I am afi*aid that the remark 

 that it "cannot be of any use" may have been made inadvertently; 

 but it may have been intended, for in the first edition the usual 

 qualification was given and must therefore have been deliberately 

 excised. Anyhow I should like to think that Darwin did throw over 

 that tuft of hair, and that he felt relief when he had done so. 

 AVliether however we have his great authority for such a course or 

 not, I feel quite sure that we shall be rightly interpreting the facts 

 of nature if we cease to expect to find purposefulness wherever we 

 meet with definite structures or patterns. Such things are, as often 



