The Making of Species 
“It follows—not as a theory but as a fact—that 
whenever an advantageous variation is needed, 
it can only consist in an increase or decrease of 
some power or faculty already existing.” Now, 
in order for an increase or decrease to occur, 
there must be something in existence to be 
increased or diminished. Wallace, it is true, 
speaks here only of powers and faculties; but 
it can scarcely be supposed that he believes that 
variations as to structure are intrinsically different 
from those relating to powers and faculties. 
4. Herbert Spencer urges, as an objection to 
the theory of natural selection, that favourable 
variations in one organ are likely to be counter- 
balanced by unfavourable variations in some 
other organ. He maintains that the chances are 
enormous against the occurrence of the “ many 
coincident and co-ordinated variations” that are 
necessary to create a life or death determining 
advantage. 
This objection was urged by a writer in the 
Edinburgh Review in January 1909, and even 
by Wallace himself in the Fortnightly Review 
last March against the mutation theory. This 
objection, strong though it appears on paper, 
exists only in the imagination of the objector. 
Those who urge it display a misunderstanding 
of the manner in which natural selection acts, and 
ignorance of the phenomenon of the correlation 
of organs. 
38 
