THE FACTOES OF ORGANIC EVOLUTION. 43 



gone on, and are ever going on, in organic bodies, from an 

 ^sij^ly^phjsical^ poin t_pf.jdew. On contemplating the 

 facts from this point of view, we become aware that, 

 besides those special effects of the co-operating forces 

 which eventuate in the longer survival of one individual 

 than of others, and in the consequent increase through 

 generations, of some trait which furthered its survival, 

 many other effects are being wrought on each and all 

 of the individuals. Bodies of every class and quality, 

 inorganic as well as organic, are from instant to instant 

 subject to the influences in their environments; are 

 from instant to instant being changed by these in ways 

 that are mostly inconspicuous; and are in course of time 

 changed by them in conspicuous ways. Living things in 

 common with dead things, are, I say, being thus perpetu 

 ally acted upon and modified; and the changes hence 

 resulting, constitute an all-important part of those under 

 gone in the course of organic evolution. I do not mean to 

 imply that changes of this class pass entirely unrecognized ; 

 for, as we shall see, Mr. Darwin takes cognizance of certain 

 secondary and special ones. But the effects which are not 

 taken into account, are those primary and universal effects 

 which give certain fundamental characters to all organisms. 

 Contemplation of an analogy will best prepare the way for 

 appreciation of them, and of the relation they bear to those 

 which at present monopolize attention. 



An observant rambler along shores, will, here and there, 

 note places where the sea has deposited things more or less 

 similar, and separated them from dissimilar things will 

 see shingle parted from sand; larger stones sorted from 

 smaller stones; and will occasionally discover deposits of 

 shells more or less worn by being tolled about. Sometimes 

 the pebbles or boulders composing the shingle at one end 

 of a bay, he will find much larger than those at the 

 other : intermediate sizes, having small average differences, 



occupying the space between the extremes. An example 

 5 



