know, can perfectly well withstand a little more heat and cold, a little
more damp and dry, but which in the metropolis of their range do not exist
in vast numbers, although if many of the other inhabitants were destroyed
[they] would cover the ground. We thus clearly see that their numbers are
kept down, in almost every case, not by climate, but by the struggle with
other organisms. All this you will perhaps think very obvious; but, until
I repeated it to myself thousands of times, I took, as I believe, a wholly
wrong view of the whole economy of nature...

HYBRIDISM.

I am so much pleased that you approve of this chapter; you would be
astonished at the labour this cost me; so often was I, on what I believe
was, the wrong scent.

RUDIMENTARY ORGANS.

On the theory of Natural Selection there is a wide distinction between
Rudimentary Organs and what you call germs of organs, and what I call in my
bigger book "nascent" organs. An organ should not be called rudimentary
unless it be useless--as teeth which never cut through the gums--the
papillae, representing the pistil in male flowers, wing of Apteryx, or
better, the little wings under soldered elytra. These organs are now
plainly useless, and a fortiori, they would be useless in a less developed
state. Natural Selection acts exclusively by preserving successive slight,
USEFUL modifications. Hence Natural Selection cannot possibly make a
useless or rudimentary organ. Such organs are solely due to inheritance
(as explained in my discussion), and plainly bespeak an ancestor having the
organ in a useful condition. They may be, and often have been, worked in
for other purposes, and then they are only rudimentary for the original