CHAPTEE VI. 



THE DEGREE OF LIFE VARIES AS THE DEGREE OF 

 CORRESPONDENCE. 



31. ALREADY it lias been shown respecting each other 

 qualification included in the foregoing definition, that the life 

 is high in proportion as that qualification is well fulfilled ; 

 and it is now to be remarked, that the same thing is especially 

 true respecting this last qualification the correspondence be- 

 tween internal and external relations. It is manifest d priori, 

 that since changes in the physical state of the environment, as 

 also those mechanical actions and those variations of available 

 food which occur in it, are liable to stop the processes going 

 on in the organism ; and since the adaptive changes in the 

 organism have the effects of directly or indirectly counter- 

 balancing these changes in the environment ; it follows that 

 the life of the organism will be short or long, low or high, 

 according to the extent to which changes in the environment 

 are met by corresponding changes in the organism. Allow- 

 ing a margin for perturbations, the life will continue only 

 while the correspondence continues ; the completeness of the 

 life will be proportionate to the completeness of the corre- 

 spondence ; and the life will be perfect only when the corre- 

 spondence is perfect. Not to dwell in general statements, 

 however, let us contemplate this truth under its concrete 

 aspects. 



32. In life of the lowest order, we find that only the 



