572 THE BEGINNINGS OF LIFE. 



their readiness to fall into new modes of combination 

 — many of which necessitate new modes of moving 

 equilibrium, which can only be brought about by the 

 production of new organic forms. 



The facts already cited suflBce, therefore, to show 

 that Natural Selection can have no sort of influence, 

 as a producer of change, over the members of that vast 

 assemblage of Infusorial and Cryptogamic organisms of 

 which the ephemeromorphic world is composed— although 

 Mr. Darwin appears to believe that the form and struc- 

 ture of ^ every living thing ' has been influenced by such 

 a set of agencies '. For independently of the fact that 

 laws of ^polarity' alone seem to prevail in determining 

 the form and structure of the ephemeromorphs, these 

 comparatively simple animal and vegetal forms are 

 derived one out of another in a manner which is so 

 irregular and variable at diflFerent times, that no ' laws 

 of heredity' can come into play. And this being the 

 case. Natural Selection cannot operate as a producer of 

 variation. For, in briefly epitomizing his doctrine of 

 Natural Selection, Mr. Darwin thus expresses it - : — ' As 

 many more individuals of each species are born than 



^ Thus Mr, Darwin says: — '^ Every detail of structure in evny living 

 creature (making some little allowance for the direct action of physical 

 conditions) may be viewed either as having been of special use to 

 some ancestral form, or as being novv of special use to some of tlie 

 descendants of this form — either directly or indirectly through the 

 complex laws of growth.' See also quotations on p. 590, and p. 607, 

 note. 



2 ' Origin of Species,' 5th ed., Introduction. 



