Natural Selection and Lamarckism. 



MR. HERBERT SPENCER still believes in the Lamarckian 

 factor in evolution as strongly as ever. In the pages of the 

 Contempovary Revieiv he claims such an " Inadequacy of Natural 

 Selection " as necessitates the introduction of the inheritance of the 

 effects of use and disuse as the only means of accounting for the facts 

 he brings forward. I propose to examine his latest arguments, and 

 to show that they are too weak to bear the superstructure which he 

 erects upon them. 



The first proof of use-inheritance' that Mr. Spencer advances is 

 the fact of the striking differences in the acuteness of the sense of 

 touch in various parts of the body as estimated by the varying 

 distances at which the points of a pair of compasses can be distinguished 

 as yielding separate and distinct sensations. He urges that these 

 differences could not be brought about by Natural Selection, or survival 

 of the fittest, and, therefore, must be due to the cumulative inheri- 

 tance of the functional modifications produced by use and disuse in 

 the individual. It is admitted, however, that a widely-diffused sense 

 of touch would be evolved by Natural Selection, as being absolutely 

 necessary for safety and continued existence ; and it should be 

 equally obvious that Natural Selection cannot act in an indiscrimi- 

 nately unvarying degree in all parts alike, but would evolve local 

 sensibilities solely in proportion to the varying degrees of the use- 

 fulness which causes its action. Mr. Spencer himself admits that the 

 high perceptive power possessed by the end of the forefinger " may " 

 have arisen by survival of the fittest ; and there ought to be no 

 difficulty in extending the concession to the other finger-tips, and to 

 other joints of the fingers and parts of the hand where it would prove 

 useful, and where its partial diffusion would be aided by the general 

 principle of correlation. The general distribution of the sense of 

 touch is in accordance with the requirements of Natural Selection. 



1 I employ this term to signify " the inheritance of the effects of use and disuse." 

 Besides being brief and convenient, it also has the advantage of not necessarily 

 including the inheritance of such acquired characters as mutilations — a subject on 

 which the more prudent Lamarckians appear to be rather sceptical. One of them, 

 indeed, has distinctly denied the inheritance of mutilations and injuries. 



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