LIFE AND MIND 



ity of correspondence is exemplified in the in- 

 terdependent progress of science and art. Here 

 again we are carried into the domain of socio- 

 logy, and this thread must be left to be gathered 

 up with the others when we come to treat of 

 intellectual progress. 



It remains to note that the extension of the 

 correspondence in space and time, and its in- 

 crease in definite heterogeneity, both heighten 

 the degree of life and add to the ability to 

 maintain life. On the one hand, the more nu- 

 merous, the more complicated, and the more 

 clearly defined are the outer relations to which 

 the organism adapts itself, and the longer the 

 interval of time by which the adjustments may 

 be made to forestall external contingencies, the 

 greater will be the number of heterogeneous 

 changes in which life consists. And on the other 

 hand, the greater the number of heterogeneous 

 changes by which the organism can respond to 

 outer changes, the more easily and surely will 

 life be prolonged. Whence, says Mr. Spencer, 

 "we may clearly see how life and ability to 

 maintain life are two sides of the same fact — 

 how life is a combination of processes, the result 

 of whose workings is their own continuance." 

 An interesting commentary on this proposition 

 is furnished by Mr. Lankester's recently pub- 

 lished essay on " Comparative Longevity," in 

 which it is shown that high individuation, or the 



