5S0 APPENDIX A. 



sensation and a motion : and we shall also find, that the test by 



which we habitually rank creatures high or low in the scale of 



vitality is the degree of co-ordination their actions exhibit. 

 ***** 



There remains but to notice the objection which possibly may 

 be raised, that the co-ordination of actions is not life, but the 

 ability to maintain life. Lack of space forbids going into this at 

 length. It must suffice to say, that life and the ability to main- 

 tain life will be found the same. We perpetually expend the 

 vitality we have that we may continue our vitality. Our power 

 to breathe a minute hence depends upon our breathing now. We 

 must digest during this week that we may have strength to digest 

 next. That we may get more food, we must use the force which 

 the food we have eaten gives us. Everywhere vigorous life is the 

 strength, activity, and sagacity whereby life is maintained ; and 

 equally in descending the scale of being, or in watching the 

 decline of an invalid, we see that the ebbing away of life is the 

 ebbing away of the ability to preserve life.* 



[Only on now coming to re-read the definition of Life enun- 

 ciated at the commencement of this essay with the arguments 

 used in justification of it, does it occur to me that its essential 

 thought ought to have been incorporated in the definition of Life 

 given in Part I. The idea of co-ordination is there implied in the 

 idea of correspondence, but the idea of co-ordination is so cardi- 

 nal a one that it should be expressed not by implication but 

 overtly. It is too late to make the required amendment in the 

 proper place, for the first part of this work is already stereotyped 

 and printed. Being unable to do better I make the amendment 

 here. The formula as completed will run :^ — The definite combi- 

 nation of heterogeneous chianges, both simultaneous and succes- 

 sive, co-ordinated into correspondence with external co- existences 

 and sequences.] 



Ending here this preliminary dissertation, let us now proceed 

 to our special subject. 



§ 1. On contemplating its general circumstances, we perceive 

 that any race of organisms is subject to two sets of conflicting 

 influences. On the one hand by natural death, by enemies, by 

 lack of food, by atmospheric changes, (fcc, it is constantly being 



* It may be needful to remark, that by the proposed expression it is 

 intended to define — not Life in its essence; bnt, Life as manifested to us — 

 not Life as a noumcnov : but, Life as a phenomenon. The ultimate mystery is 

 as great as ever : seeing that there remains unsolved the question — What 

 determines the co-ordination of actions ? 



