THE LIFE VARIES AS THE CORRESPOXDENCE. 83 



most prevalent coexistences and sequences in tlie environ- 

 ment, have any simultaneous and successive changes answer- 

 ing to them in the organism. A plant's vital processes 

 display adjustment solely to the continuous coexistence of 

 certain elements and forces surrounding its roots and leaves ; 

 and vary only with the variations produced in these ele- 

 ments and forces by the sun — are unaffected by the countless 

 mechanical and other changes occurring around ; save when 

 accidentally arrested by these. The life of a worm is made 

 up of actions referring almost exclusively to the tangible pro- 

 perties of adjacent things. All those visible and audible 

 changes which happen near it, and are connected with other 

 changes that may presently destroy it, pass unrecognized — 

 produce in it no adapted changes : its only adjustment of in- 

 ternal relations to external relations of this order, is seen 

 w^hen it escapes to the surface on feeling the vibrations pro- 

 duced by an approaching mole. Adjusted as are the pro- 

 ceedings of a bird, to a far greater number of coexistences and 

 sequences in the environment, cognizable by sight, hearing, 

 scent, and their combinations ; and numerous as are the 

 dangers it shuns and the needs it fulfils, in virtue of this ex- 

 tensive correspondence ; it exhibits no such actions as those 

 by which a human being counterbalances variations in tem- 

 perature and supply of food, consequent on the seasons. And 

 when we see the plant eaten, the worm trodden on, the bird 

 dead from starvation ; we see alike that the death is an arrest 

 of such correspondence as existed ; that it occurred when 

 there was some change in the environment to which the or- 

 ganism made no answ^ering change ; and that thus, both in 

 shortness and simplicity, the life was incomplete in propor- 

 tion as the correspondence was incomplete. Progress towards 

 more prolonged and higher life, evidently implies an ability 

 to respond to less general coexistences and sequences. Each 

 step upwards must consist in adding to the previously-adjasted 

 relations which the organism exhibits, some further relation 

 parallel to a further relation in the environment. And the 



