been formed for the purpose of combating other stags, for the exclusive
possession of the females; who are observed like the ladies in the times
of chivalry to attend the car of the victor.

"The birds which do not carry food to their young, and do not therefore
marry, are armed with spurs for the purpose of fighting for the
exclusive possession of the females, as cocks and quails. It is certain
that these weapons are not provided for their defence against other
adversaries, because the females of these species are without this
armour. The final cause of this contest among the males seems to be
_that the strongest and most active animal should propagate the species,
which should thence become improved_."[180]

Dr. Darwin would have been on stronger ground if he had said that the
_effect_ of the contest among the males was that the fittest should
survive, and hence transmit any fit modifications which had occurred to
them as vitally true, rather than that the desire to attain this end had
caused the contest; but either way the sentence just given is sufficient
to show that he was not blind to the fact that the fittest commonly
survive, and to the consequences of this fact. The use, however, of the
word "thence," as well as of the expression "final cause," is loose, as
Dr. Darwin would no doubt readily have admitted. Improvement in the
species is due quite as much, by Dr. Darwin's own showing, to the causes
which have led to such and such an animal's making itself the fittest,
as to the fact that if fittest it will be more likely to survive and
transmit its improvement. There have been two factors in modification;
the one provides variations, the other accumulates them; neither can
claim exclusive right to the word "thence," as though the modification
was due to it and to it only. Dr. Darwin's use of the word "thence"
here is clearly a slip, and nothing else; but it is one which brings him
for the moment into the very error into which his grandson has fallen
more disastrously.

"Another great want," he continues, "consists in the means of procuring
food, which has diversified the forms of all species of animals. Thus
the nose of the swine has become hard for the purpose of turning up the
soil in search of insects and of roots. The trunk of the elephant is an
elongation of the nose for the purpose of pulling down the branches of
trees for his food, and for taking up water without bending his knees.
Beasts of prey have