mmarize the results of the foregoing
analysis, in order that we may approach the biological study of human
associations with definite and clear conceptions of the fundamental laws
controlling living communities of all grades.

We have dealt mainly with _Amoeba_, _Hydra_, and the ant-community
which exemplify three somewhat distinct types of organic individuality.
Some of the transitional forms have been specified to show how the second
kind originates from the first, and how in its turn this grows in time
into the third and most complex association; thus _Vorticella_ and
_Volvox_ connect _Amoeba_ with the cell-community individual like
_Hydra_ and a solitary wasp, while the annually established colonies of
social wasps and of bumblebees lead to the permanent colony-individual.
Restricting attention to the three primary examples, and remembering that
the criterion of completeness is the ability to discharge satisfactorily
all of the eight biological tasks, it is clear that the entire _Hydra_ and
the whole ant-community correspond _physiologically_ with _Amoeba_,
although the first-named is _structurally_ a cell-community equivalent to
many protozoa, and the insect colony is composed of many such
cell-communities as elements. In the third type, neither a single queen
nor a single worker is able to carry on all of the biological tasks any
more than a muscle-cell or an unformed egg of _Hydra_ can maintain itself
capably in isolation. Therefore the ant-society as a whole and the _Hydra_
in its entirety are organic individuals on the same physiological plane
with _Amoeba_, and they are equally subject to the same great laws of
nature demanding selfish maintenance and racial perpetuation.

But we must not lose sight of the fundamental value of the unit during the
evolution of a higher from a lower type. The tissue-cell of _Hydra_ must
still obey the mandate to live an efficient personal life, because this is
necessary for the welfare of other cells and of the whole complex. The
original egoistic tasks are not abolished, but new duties are added to
them in ways we have learned to distinguish. In _Vorticella_ the products
of fission do not separate, and certain advantages accrue from the organic
continuity thus maintained. The success of _Hydra_ in its ceaseless
struggle to live depends wholly upon the cooperation of its differentiated
cell-units, now no longer equivalent in function to the all-powerful
_Amoeba_, although each