24 ON THE LAW WHICH HAS REGULATED 
Do they not teach us something of the system ot 
Nature? If each species has been created inde- 
pendently, and without any necessary relations with 
pre-existing species, what do these rudiments, these 
apparent imperfections mean? There must be a 
cause for them; they must be the necessary results 
of some great natural law. Now, if, as it has been 
endeavoured to be shown, the great law which has 
regulated the peopling of the earth with animal and 
vegetable life is, that every change shall be gradual; 
that no new creature shall be formed widely differing 
from anything before existing; that in this, as in 
everything else in Nature, there shall be gradation 
and harmony,—then these rudimentary organs are 
necessary, and are an essential part of the system of 
Nature. Ere the higher Vertebrata were formed, for 
instance, many steps were required, and many organs 
had to undergo modifications from the rudimental 
condition in which only they had as yet existed. 
We still see remaining an antitypal sketch of a wing 
adapted for flight in the scaly flapper of the penguin, 
and limbs first concealed beneath the skin, and then 
weakly protruding from it, were the necessary gra- 
dations before others should be formed fully adapted 
for locomotion.* Many more of these modifica 
tions should we behold, and more complete series 
* The theory of Natural Selection has now taught us that 
these are not the steps by which limbs have been formed; and 
that most rudimentary organs have been produced by abortion 
owing to disuse, as explained by Mr. Darwin. 
