NATURAL SELECTION 151 



Without these general conditions of force, tending 

 to evolution, what would become of natural 

 selection, deprived of the faculty that organic 

 matter has of adapting itself to its medium ? What 

 would become of natural selection itself, without 

 heredity ? 



Adaptation, selection, and heredity are the factors 

 by which every organism is developed, and they are 

 in intimate and direct dependence upon another 

 great factor, medium, which in turn is bound to 

 universal energetic. So that there is an immense 

 difference between what is really the struggle for 

 life, as one of the elements of evolution, compared 

 with the enormous preponderance which usually is 

 gratuitously ascribed to it. 



The struggle for life of itself would be nothing, 

 had it not, as inseparable complementary com- 

 panions, adaptation and heredity; and these, in 

 their turn, would not exist without the general 

 laws of mechanics, which include equally crude 

 matter and live matter. And this, which is 

 commonly the key that claims to explain even 

 social phenomena, passes on to a third term, as it 

 depends not only on the cosmic environment, but 

 is also subordinated to adaptation and heredity, and 

 in its last term to the rhythms of force, from which 

 start all initial energies. 



Note the case of the Mexican axolotl, quoted 



