THE LAW OF PROGRESS. 277 



generations by inheritance, whilst the intermediate forms 

 die out, they form independent " new species." The origin 

 of new species by division of labour, or separation, diver- 

 gence, or differentiation of varieties, is therefore a necessary 

 consequence of natural selection. ^^ 



The same kind of interest attaches to a second great law 

 which we deduce from natural selection, and which is, indeed, 

 closely connected with the law of Divergence, but in no way 

 identical with it ; namely, the law of Progress (progressus), 

 or Perfecting (teleosis). (Gen. Morph. ii. 257). This great 

 and important law, like the law of differentiation, had 

 long been empirically established by palseontological ex- 

 perience, before Darwin's Theory of Selection gave us the 

 key to the explanation of its cause. The most distinguished 

 palseontologists have pointed out the law of progress as the 

 most general result of their investigations of fossil organisms. 

 This has been specially done by Bronn, whose investiga- 

 tions on the laws of construction ^^ and the laws of the 

 development ^^ of organisms, although little heeded, are 

 excellent, and deserve most careful consideration. The 

 general results of the law of differentiation and the law of 

 progress, at which Bronn arrived by a purely mechanical 

 hypothesis, and by exceedingly accurate, laborious, and care- 

 ful investigations, are brilliant confirmations of the truth of 

 these two great laws which we deduce as necessary in- 

 ferences from the theory of selection. 



The law of progress or of perfecting establishes the ex- 

 ceedingly important fact, on the ground of palseontologi- 

 cal experience, that in successive periods of this earth's 

 history, a continual increase in the perfection of organic 

 formations has taken place. Since that inconceivably 



