64 GERMINAL SELECTION. 



the degeneration of superfluous parts, that a heredity 

 of acquired characters would perform, without render- 

 ing necessary so violent an assumption. I have always 

 conceded that many transformations actually do run 

 parallel to the use and disuse of the parts, 1 that there- 

 fore it does really look as if functional acquisitions of 

 the individual life were hereditary. But if it be found 

 that passively functioning parts, that is, parts which 

 are not alterable during the individual life by function, 

 obey the same laws and also degenerate when they be- 

 come useless, then we shall scarcely be able to refuse 

 our assent to a view which explains both cases. It 

 certainly cannot be the physiological function which 

 provokes modifications in the individual, which are 

 then subsequently transmitted to the germ and in this 

 way made hereditary, if funciionless parts also change 

 when they become useless. It is precisely this useless- 

 ness, then, from which the initial impulse emanates, 

 and the primary modification is not in the soma but 

 in the germ. 



The Lamarckians were right when they maintained 

 that the factor for which hitherto the name of natural 

 selection had been exclusively reserved, viz., personal 

 selection, was insufficient for the explanation of the 

 phenomena. They were also right when they declared 

 that panmixia in the form in which until recently I 

 held the theory was also insufficient to explain the 

 degeneration of parts that had grown useless, but they 



1 Poulton has adverted to the fact that this is neverthe- 

 less not always the case; for example, it is not so with the 

 teeth, whose shape it had also been sought to reduce to 

 the mechanical effects of pressure and friction. See "The 

 Theory of Selection" in The Proceedings of the Boston So- 

 ciety of Natural History, Vol. XX., page 389. 1894. 



