CHAP. IX.] NATUKAL SELECTION. 285 



creature presenting them, by enabling it to obtain food, 

 escape enemies, and propagate its kind. But once more be 

 says : 



&quot; We have seen that species at any one period are not indefinitely 

 variable, and are not linked together by a multitude of intermediate 

 gradations, partly because the process of natural selection will always 

 be very slow, and will act, at any one time, only on a very few forms ; 

 and partly because the very process of natural selection almost implies 

 the continual supplanting and extinction of preceding and intermediate 

 gradations.&quot; p. 223. 



Such are Mr. Darwin s earlier statements. At present 

 we read as follows : HIS later 



views 



&quot; 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 probably attributed too much to the action of 

 natural selection or the survival of the fittest I had not for 

 merly sufficiently considered the existence of many structures which 

 appear to be, as far as we can judge, neither beneficial nor injurious ; 

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

 my work.&quot; Descent of Man, vol. i. p. 152. 



A still more remarkable admission is that in which he 

 says of the causes of change in organisms : 



&quot; We can only say they relate much more closely to the constitution 

 of the varying organism, than to the nature of the conditions to which 

 it has been subjected. An unexplained residuum of change, perhaps a 

 large one, must be left to the assumed action of those unknown agencies, 

 which occasionally induce strongly marked and abrupt deviations of 

 structure in our domestic productions.&quot; vol. i. p. 154. 



But perhaps the most glaring contradiction is presented by 

 the following passage : 



&quot; No doubt man, as well as every other animal, presents structures 

 which, as far as we can judge with our little knowledge, are not now 

 of any service to him, nor have been so during any former period of 

 his existence, either in relation to his general conditions of life, or of 

 one sex to the other. Such structures cannot be accounted for by amj 

 form of selection, or by the inherited effects of the use and disuse of 

 parts. We know, however, that many strange and strongly marked 

 peculiarities of structure occasionally appear in our domesticated pro 

 ductions ; and if the unknown caiises which produce them were to act 



