The life of this example, representing the whole series of one-celled organisms, is almost infinitely simpler than that of a member of a human community, yet it reveals the beginnings of certain characteristics of the latter. Here, it is true, the natural obligations in question are not like those which are ordinarily denoted social, but it is equally true that even in this most elementary instance a living thing does not live unto itself alone. It is easy to see the value to the species as a whole of obedience to the second great law--"_Preserve thy kind_." But a little further thought makes it plain that even the performance of acts in compliance with the first mandate--"_preserve thyself_"--are not purely selfish, although their immediate value is realized as individual benefit. Surely an organism that failed to live an efficient individual life would be ineffective in reproduction, so that from one point of view everything an animal does is tributary to the culminating act performed for the larger good of the life of the whole species. It is a nice balance that nature has worked out in _Amoeba_, as well as in all other cases, between the personal life of the individual, complete only when the final process of multiplication supervenes, and this process itself, which demands an efficient performance, even though this is destructive of the performer. Before passing to the next members of the series, which reveal additional principles more truly social in the human sense, let us pause to note that already we have found certain natural criteria that belong in the department of ethics. Even in the case of the biological unit like _Amoeba_, which is entirely solitary and unrelated to other individuals of its kind excepting in so far as it is a link in the chain of successive generations, any vital activity can be called good or bad, right or wrong. Nature judges an act good and right if it tends to preserve the animal and the species; an act is wrong and evil if it is biologically destructive of the animal or if it interferes with the perpetuation of its kind. Again it must be pointed out that these terms are human words, employed for the complex conceptions that belong alone to retrospective and contemplative human consciousness to most of us they seem to imply the existence of some absolute standard or ideal by which a given act may be tested to see if it is right or the opposite.