mpersonal view is well-nigh
impossible. Step by step we will then work up the scale of social
morphology, approaching in the natural evolutionary order that part of the
subject which interests us most deeply.

Just as the construction of an edifice must begin with the fashioning of
the individual brick and bolt and girder, so the evolution of a biological
association begins with the unitary organisms consisting of single cells,
like _Amoeba_. We have had occasion to discuss this animal many times
in our previous studies of one or another aspect of evolution, and once
again we must return to it in order to reestablish certain points that are
of fundamental importance for our present purposes. Within the limits of
its simple body, _Amoeba_ performs the several tasks which nature
demands a living thing shall do; it feeds and respires and moves,
continually utilizing matter and energy obtained from the environment for
the reconstruction of its substance and replenishment of its vital powers;
it cooerdinates the activities of its simple body, and by its reflex
responses to environmental influences it maintains its adjustment to the
external conditions of life. The animal does all of these things with a
purely individual benefit, namely, the prolongation of its own life. While
it is performing these individual tasks, it does not concern itself with
anything else but its own welfare; the interests of other living things
are not involved in any way, excepting in the case of other organisms that
may serve the animal as food. _Amoeba_, like every other living thing,
if it is to exist, must unconsciously obey the first great commandment of
nature,--"_Preserve thyself_."

But its life is incomplete if it stops with the furtherance of aims that
we may call purely selfish. Nature also demands that an _Amoeba_, again
like every other living thing, shall perpetuate its kind. The mode by
which it reproduces is ordinarily quite simple; the animal grows to a
certain bulk and then it divides into two masses of protoplasm, each of
which receives a portion of the mother nucleus. Sometimes by a peculiar
process it breaks up into numerous small fragments called spores, which
also receive portions of the parent nucleus. The most striking feature in
both kinds of reproduction in _Amoeba_ is the complete destruction of
the individual parent that exists before the act and does not afterwards.
It is quite true that every part of the mother animal