ly lead to the extinction of those groups with which they do
not enter into close competition. In some cases, lowly organized forms
appear to have been preserved to the present day from inhabiting
confined or peculiar stations, where they have been subjected to less
severe competition and where their scanty numbers have retarded the
chance of favorable variations arising.

Finally, I believe that many lowly organized forms now exist throughout
the world from various causes. In some cases variations or individual
differences of a favorable nature may never have arisen for natural
selection to act on and accumulate. In no case, probably, has time
sufficed for the utmost possible amount of development. In some few
cases there has been what we must call retrogression of organization.
But the main cause lies in the fact that under very simple conditions of
life a high organization would be of no service--possibly would be of
actual disservice, as being of a more delicate nature and more liable to
be put out of order and injured.

4. Man: An Adaptive Mechanism[187]

Everything in nature, living or not living, exists and develops at the
expense of some other thing, living or not living. The plant borrows
from the soil; the soil from the rocks and the atmosphere; men and
animals take from the plants and from each other the elements which they
in death return to the soil, the atmosphere, and the plants. Year after
year, century after century, eon after eon, the mighty, immeasurable,
ceaseless round of elements goes on, in the stupendous process of
chemical change, which marks the eternal life of matter.

To the superficial observer, nature in all her parts seems imbued with a
spirit of profound peace and harmony; to the scientist it is obvious
that every infinitesimal particle of the immense concourse is in a state
of desperate and ceaseless struggle to obtain such share of the
available supply of matter and energy as will suffice to maintain its
present ephemeral form in a state of equilibrium with its surroundings.
Not only is this struggle manifest among living forms, among birds and
beasts and insects in their competition for food and habitat, but--if we
may believe the revelations of the science of radio-activity--a process
of transmutation, of disintegration of the atoms of one element with
simultaneous formation of another element, is taking place in every
fragment of inanimate matter, a process which parallels in ch