Chap. II. Manner of Development. 6 1 



and continually used during past ages for some useful purpose, 

 would probably become firmly fixed, and might be long inherited. 



Thus a large yet undefined extension may safely be given to 

 the direct arid indirect results of natural selection ; but I now 

 admit, after reading the essay by Nageli on plants, and the 

 remarks by various authors with respect to animals, more 

 especially those recently made by Professor Broca, that in the 

 earlier editions of my ' Origin of Species ' I perhaps attributed 

 too much to the action of natural selection or the survival of 

 the fittest. I have altered the fifth edition of the ' Origin ' so as to 

 confine my remarks to adaptive changes of structure ; but I am 

 convinced, from the light gained during even the last few years, 

 that very many structures which now appear to us useless, wull 

 hereafter be proved to be useful, and will therefore come within 

 the range of natural selection. Nevertheless, I did not formerly 

 consider sufficiently the existence of structures, which, as far as 

 we can at present judge, are neither beneficial nor injurious; 

 and this I believe to be one of the greatest oversights as yet 

 detected in my work. I may be permitted to say, as some 

 excuse, that I had two distinct objects in view ; firstly, to 

 shew that species had not been separately created, and secondly, 

 that natural selection had been the chief agent of change, 

 though largely aided by the inherited effects of habit, and slightly 

 by the direct action of the surrounding conditions. I was 

 not, however, able to annul the influence of my former belief, 

 then almost universal, that each species had been purposely 

 created ; and this led to my tacit assumption that every detail 

 of structure, excepting rudiments, was of some special, though 

 unrecognised, service. Any one with this assumption in his 

 mind would naturally extend too far the action of natural 

 selection, either during past or present times. Some of those 

 who admit the principle of evolution, but reject natural selec- 

 tion, seem to forget, when criticising my book, that I had the 

 above two objects in view ; hence if I have erred in giving to 

 natural selection great power, which I am very far from 

 admitting, or in having exaggerated its power, which is in itself 

 probable, I have at least, as I hope, done^good service in aiding 

 to overthrow the dogma of separate creations. 



It is, as I can now see, probable that all organic beings, 

 including man, possess peculiarities of structure, which neither 

 are now, nor were formerly of any service to them, and which, 

 therefore, are of no physiological importance. We know not 

 what produces the numberless slight differences between the 

 individuals of each species, for reversion only carries the 

 problem a few steps backwards; but each peculiarity must 



