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as though Natural Selection were an essential factor in the 
process. In his Origin of Species he does this the very 
first time that he makes mention of correlated variation. 
“ I mean by this expression (correlated variation) that the whole 
organisation is so tied together during its growth and development, 
that when slight variations in any one part occur, and are accumu 
lated through Natural Selection, other parts become modified.”— 
(■Origin of Species, p. 114.) 
He speaks to the same effect in The Variation of Animals 
and Plants:— 
“ Correlated variation is an important subject for us, for when one 
part is modified, through continued selection, either by man or under 
nature, other parts of the organisation will be unavoidably modified.”— 
(Vol. ii., p. 320.) 
Mr. Fiske recognises the principle of correlated variation 
as the ally of Natural Selection. He says :— 
“ It is enough for the purposes of the Darwinian theory to know 
that they (the laws of correlated growth) exist. For, taken all 
together, they show that natural selection operating on even the 
most superficial variations is quite competent to work deep-seated 
changes of structure and function.”—(Darwinism and other Essays, 
p. 17.) 
And now, leaving loose definitions and curious modes of 
stating cases, let us ask what ground there is for attributing 
any influence to Natural Selection in this connection. 
We are told that when one part is modified by selection, 
other parts of the organism will be unavoidably modified. 
This is true of artificial selection and may possibly be 
true of Natural Selection also. Assuming, for the sake of 
argument, that it is true, we must not be led away by 
this assertion to believe that correlated variation is 
necessarily dependent upon the initiative of the principle 
of selection. We have seen by Mr. Darwin’s own showing 
that Natural Selection may not in some cases, and cannot 
in others, influence correlated variation.