514 EQUILIBRATION. 



daily expenditure of force, and the amount of latent force 

 daily added. The like must manifestly be the case with 

 all organic modifications consequent on change of climate 

 or food. This is a conclusion which we may safely draw 

 without knowing the special re-arrangements that effect the 

 equilibration. If we see that a different mode of life is 

 followed, after a period of functional derangement, by some 

 altered condition of the system — if we see that this altered 

 condition, becoming by and by established, continues with- 

 out further change; we have no alternative but to say, that 

 the new forces brought to bear on the system, have been 

 compensated by the opposing forces they have evoked. 

 And this is the interpretation of the process which we call 

 adaptation. Finally, each organism illustrates the 



law in the ensemhle of its life. At the outset it daily absorbs 

 under the form of food, an amount of force greater than it 

 daily expends; and the surplus is daily equilibrated by 

 groAvth. As maturity is approached, this surplus dimin- 

 ishes; and in the perfect organism, the day's absorption of 

 potential motion balances the day's expenditure of actual 

 motion. That is to say, during adult life, there is continu- 

 ously exhibited an equilibration of the third order. Even- 

 tually, the daily loss, beginning to out-balance the daily 

 gain, there results a diminishing amount of functional ac- 

 tion; the organic rhythms extend less and less widely on 

 each side of the medium state ; and there finally results that 

 complete equilibration which we call death. 



The ultimate structural state accompanying that ulti- 

 mate functional state towards which an organism tends, both 

 individually and as a species, may be deduced from one of 

 the propositions set down in the opening section of this chap- 

 ter. AVe saw that the limit of heterogeneity is arrived at 

 whenever the equilibration of any aggregate becomes com- 

 plete — that the re-distribution of matter can continue so 

 long only as there continues any motion unbalanced. 

 Whence we found it to follow that the final structural ar- 



