THEORIES OF LAMARCK AND DARWIN 389 
tomed to display their tail-feathers; the one with the most 
attractive display excites the pairing instinct in the highest 
degree, and becomes the selected suitor. In this way, 
through the operation of a form of selection which Darwin 
designates sexual selection, possibly such curious adaptations 
as the peacock’s tail may be accounted for. 
It should be pointed out that this part of the theory is 
almost wholly discredited by biologists. Experimental evi- 
dence is against it. Nevertheless in a descriptive account 
of Darwin’s theory it may be allowed to stand without 
critical comment. 
Inadequacy of Natural Selection.—In nature, under the 
struggle for existence, the fittest will be preserved; and natural 
selection will operate toward the elaboration or the suppres- 
sion of certain organs or certain characteristics when the elab- 
oration or the suppression is of advantage to the animal form. 
Much has been said of late as to the inadequacy of natural 
selection. Herbert Spencer and Huxley, both accepting 
natural selection as one of the factors, doubted its complete 
adequacy. 
One point is often overlooked, and should be brought out 
with clearness; viz., that Darwin himself was the first to 
point out clearly the inadequacy of natural selection as a 
universal law for the production of the great variety of 
animals and plants. In the second edition of the Origin oj 
Species he says: “But, as my conclusions have lately been 
much misrepresented, and it has been stated that I attribute 
the modification of species exclusively to natural selection, 
I may be permitted to remark that in the first edition of this 
work and subsequently I placed in a most conspicuous 
position, —namely, at the close of the introduction—the follow- 
ing words: ‘I am convinced that natural selection has been 
the main, but not the exclusive means of modification.’ This 
has been of no avail. Great is the power of steady mis- 
