INDIRECT EQUILIBRATION. 547 



some now kind of prey, which is abundant at seasons when 

 other prey is scarce. Now what is the process by which the 

 moving equilibrium in any species becomes adapted to some 

 additional external factor furthering its maintenance? In- 

 stead of an increased resistance to be met and counter- 

 balanced, there is here a diminished resistance; and the 

 diminished resistance is equilibrated in the same way as the 

 increased resistance. As, in the one case, there is a more 

 frequent survival of individuals whose peculiarities enable 

 them to resist the new adverse factor; so, in the other case, 

 there is a more frequent survival of individuals whose pecu- 

 liarities enable them to take advantage of the new favourable 

 factor. In each memb?r of the species, the balance of func- 

 tions and correlated arrangement of structures, differ slightly 

 from those existing in other members. To say that among 

 all its members, one is better fitted than the rest to benefit 

 by some before-unused agency in the environment, is to say 

 that its moving equilibrium is, in so far, more stably adjusted 

 to the sum of surrounding influences. And if, consequently, 

 this individual maintains its moving equilibrium when others 

 fail, and has offspring which $0 the like that is, if indivi- 

 duals thus characterized multiply and supplant the rest; 

 there is, as before, a process which effects equilibration be- 

 tween the organism and its environment, not immediately 

 but mediately, through the continuous intercourse between 

 the species as a whole and the environment. 



168. Thus we see that indirect equilibration does what- 

 ever direct equilibration cannot do. All these processes by 

 which organisms are re-fitted to their ever-changing environ- 

 ments, must be equilibrations of one kind or other. As 

 authority for this conclusion, we have not simply the uni- 

 versal truth that change of every order is towards equili- 

 brium; but we have also the truth that life itself is a 

 moving equilibrium between inner and outer actions a con- 

 tinuous adjustment of internal relations to external relations ; 



