Notices of New Books. 7601 



a suitable place in the circle of creation, as the human family forms 

 in the social scale an infinity of indefinable grades, each unmolested 

 by its neighbour. *" 



■»' The influence that the wide dispersal of the individuals of a species 

 would have in counteracting the effect of competition and extinction, 

 in weeding out the continual production of intermediate forms, is 

 another point that should be considered with reference to Mr. Dar- 

 win's argument in explanation of the individuality of species. Com- 

 petition can only take place between the individuals of a species where 

 there is actual association. In the case of animals the regions of 



competition will be wide in proportion to their means of ranging, and 

 the theory might hold good to a practical extent, for as the weaker in- 

 dividuals were being reduced by improved variations there would be no 

 difficulty in supposing that the stronger could soon occupy by migration 

 the whole geographical range of the species, and thus quite outstrip 

 their inferior progenitors. But with plants this uniform interchanging 

 competition could not take place, because there is not continual inter- 

 migration. Suppose, for. example, the case of any common plant 

 distributed throughout the whole of England or Europe, as Athyrium 

 Filix-foemina, and admit in all its fulness Mr. Darwin's theory of vari- 

 ation, that the Athyrium is continually throwing off slightly varying 

 descendants, and that the improved forms are supplanting their infe- 

 rior progenitors. Now there must be some limit to the range within 

 which these circles of competition take place, for no one would be bold 

 enough to say that the different grades of variation of a species growing 

 in Devonshire are competing with the different grades of variation of 

 the same species growing in Norfolk, or, taking a larger view, that the 

 individuals growing in Spain are competing with those growing in 

 Russia; indeed, not only is there every grade of variation, but there 

 must be every gradation in competition, proportionate to geographical 

 severance, and we ought certainly to find every gradation of result 

 and the very process of the individualization of species thereby neu- 

 tralized ; for instance, supposing an improved variation is thrown off 

 in Norfolk, the individuals in Devonshire would be none the worse for 

 this, unless the improved form could exterminate its normal progenitor 

 where it originated, and gradually spread to Devonshire ; another vari- 

 ation may be thrown off in Devonshire, and retained within a distinct 

 range of competition to the Norfolk district, and thus several forms 

 might be preserved from extinction, for unless every improved step of 

 variation could extend itself over the whole geographical range of the 

 .. VOL. XIX. 2 R 



