CHAPTEE XII. 



INDIRECT EQUILIBRATION". 



§164. Besides those perturbations produced in any organ- 

 ism by special disturbing forces, there are ever going on many 

 others — the reverberating effects of disturbing forces pre- 

 viously experienced by the individual, or by ancestors; 

 and the multiplied deviations of function so caused imply 

 multiplied deviations of structure. In § 155 there was 

 re-illustrated the truth, set forth at length when treating of 

 Adaptation (§ 69), that an organism in a state of moving 

 equilibrium, cannot have extra function thrown on any organ, 

 and extra growth produced in such organ, without correlative 

 changes being entailed throughout all other functions, and 

 eventually throughout all other organs. And when treating 

 of Variation (§ 90), we saw that individuals which have been 

 made, by their different circumstances, to deviate functionally 

 and structurally from the average type in different directions, 

 will bequeath to their joint offspring, compound perturbations 

 of function and compound deviations of structure, endlessly 

 varied in their kinds and amounts. 



Now if the individuals of a species are thus necessarily 

 made unlike in countless ways and degrees — if in one in- 

 dividual the amount of energy in a particular direction' is 

 greater than in any other individual, or if here a peculiar 

 combination gives a resulting action which is not found else- 

 where; then, among all the individuals, some will be less 

 liable than others to have their equilibria overthrown by 



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