GENESIS OF MAN, INTELLECTUALLY 



so much to confirm the theory of the descent 

 of man from an ape-like animal, — which I re- 

 gard as already sufficiently proved by the evi- 

 dence presented in the ninth chapter, — as to 

 illustrate the true point of view from which the 

 evolution of humanity should be regarded. In 

 treating of the Doctrine of Evolution in gen- 

 eral we saw it to be a corollary from the persist- 

 ence of force that the process of evolution, which 

 at first goes on with comparative slowness, must, 

 owing to the multiplication of effects, go on with 

 increasing rapidity.^ We have seen, besides, 

 that those most conspicuous aspects of evolu- 

 tion which consist in increase of definite com- 

 plexity in structure and function must be much 

 more conspicuous in the more compound than 

 in the more simple kinds of evolution. In illus- 

 tration of these closely allied truths, we may 

 note that in all cases a long period of time 

 elapses before any lower order of evolution 

 gives rise to a distinctly higher order. Long 

 ages must have passed before the slow integra- 

 tion of our solar nebula into a planetary system 

 resulted in the appearance of distinctly geologic 

 phenomena upon the several planets. Again, 

 it was a long time before geologic evolution had 

 proceeded sufficiently far to admit of the evolu- 

 tion of life — upon Saturn and Jupiter, as we 



* See above, vol. ii. p. 246. This wsls also hinted at the 

 close of the chapter on Life as Adjustment. 



57 



