CORRESPONDENCE BETWEEN LIFE AND ITS CIRCUMSTANCES. 79 



tain verbal imperfections in the definition, which it seems 

 impossible to avoid. It may be fairly urged that the word 

 correspondence will not include, without straining, the various 

 relations to be expressed by it. It may be asked : — How can 

 the continuous processes of assimilation and respiration, cor- 

 respond with the co-existence of food and oxygen in the en- 

 vironment ? or again : — How can the act of secreting some 

 defensive fluid, correspond with some external danger which 

 may never occur ? or again : — How can the dynamical phe- 

 nomena constituting perception, correspond with the statical 

 phenomena of the solid body perceived ? The only reply to 

 these questions, is, that we have no word sufficiently general 

 to comprehend all forms of this relation between the organ- 

 ism and its medium, and yet sufficiently specific to convey an 

 adequate idea of the relation ; and that the word correspond- 

 ence seems the least objectionable. The fact to be expressed 

 in all cases, is, that certain changes, continuous or discon- 

 tinuous, in the organism, are connected after such a manner 

 that, in their amounts, or variations, or periods of occurrence, 

 or modes of succession, they have a reference to external ac- 

 tions, constant or serial, actual or potential — a reference such 

 that a definite relation among any members of the one group, 

 implies a definite relation among certain members of the 

 other group ; and the word correspondence appears the best 

 fitted to express this fact. 



§ 30. The presentation of the phenomena under this ge- 

 neral form, sui^ests how our definition of Life mav be reduced 

 to its most abstract shape ; and perhaps its best shape. By 

 regarding the respective elements of the definition as relations, 

 we avoid both the circumlocution and the verbal inaccuracy ; 

 and that we may so regard them with propriety is obvious. 

 If a creature's rate of assimilation is increased in consequence 

 of a decrease of temperature in the environment ; it is that 

 the relation between the food consumed and heat produced, is 

 so re-adjusted by multiplying both its members, that the 



