comparison. It follows, that even admitting the modifying effects of
the environment, and that such modifications are inherited, they would
yet be entirely swamped by the greater effects of fortuitous variation,
and the far more rapid cumulative results of the selection of such
variations.

_Supposed Action of the Environment in Initiating Variations._

It is, however, urged that the reaction of the environment initiates
variations, which without it would never arise; such, for instance, as
the origin of horns through the pressures and irritations caused by
butting, or otherwise using the head as a weapon or for defence.
Admitting, for the sake of argument, that this is so, all the evidence
we possess shows that, from the very first appearance of the rudiment of
such an organ, it would vary to a greater extent than the amount of
growth directly produced by use; and these variations would be subject
to selection, and would thus modify the organ in ways which use alone
would never bring about. We have seen that this has been the case with
the branching antlers of the stag, which have been modified by
selection, so as to become useful in other ways than as a mere weapon;
and the same has almost certainly been the case with the variously
curved and twisted horns of antelopes. In like manner, every conceivable
rudiment would, from its first appearance, be subject to the law of
variation and selection, to which, thenceforth, the direct effect of the
environment would be altogether subordinate.

A very similar mode of reasoning will apply to the other branch of the
subject--the initiation of structures and organs by the action of the
fundamental laws of growth. Admitting that such laws have determined
some of the main divisions of the animal and vegetable kingdom, have
originated certain important organs, and have been the fundamental cause
of certain lines of development, yet at every step of the process these
laws must have acted in entire subordination to the law of natural
selection. No modification thus initiated could have advanced a single
step, unless it were, on the whole, a useful modification; while its
entire future course would be necessarily subject to the laws of
variation and selection, by which it would be sometimes checked,
sometimes hastened on, sometimes diverted to one purpose, sometimes to
another, according as the needs of the organism, under the special
conditions of its existence, required such mo