f 
iy 
. 
MR. DARWIN’S CRITICS 181 
lent example of this class of difficulties is to be 
found in Mr. Mivart’s chapter on “ Independent 
"Similarities of Structure.” Mr. Mivart says that 
- these cannot be explained by an “absolute and 
_ pure Darwinian,” but “that an innate power and 
evolutionary law, aided by the corrective action 
of natural selection, should have furnished like 
needs with like aids, is not at all improbable” 
by an “absolute and pure Darwinian ; 
(p. 82). 
I do not exactly know what Mr. Mivart means 
” indeed 
_ Mr. Mivart makes that creature hold so many 
‘singular opinions that I doubt if I can ever have 
seen one alive. But I find nothing in his 
statement of the view which he imagines to be 
originated by himself, which is really inconsistent 
with what I understand to be Mr. Darwin’s views. 
I apprehend that the foundation of the theory 
of natural selection is the fact that living bodies 
tend incessantly to vary. This variation is neither 
indefinite, nor fortuitous, nor does it take place in 
ail directions, in the strict sense of these words. 
Accurately speaking, it is not indefinite, nor 
does it take place in all directions, because it is 
limited by the general characters of the type to 
which the organism exhibiting the variation 
belongs. A whale does not tend to vary in the 
direction of producing feathers, nor a bird in the 
direction of developing whalebone. In popular 
language there is no harm in saying that the 
