THE LAW OF PROGRESS. 2h 
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 RECs 
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 palzeontological ex- 
perience, before Darwin’s Theory of Selection gave us the 
key to the explanation of its cause. The most distinguished 
palzontologists 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 palzeontologi- 
eal 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 
