Among the Caeienterata integration produces half-fused colonies of typesunlike these. There are the branched Hydrozoa in which many individuals forman aggregate in such a way as to have a common system of nutrition, whilesome of them undertake special functions; and much the same may be said ofthose compound Actinozoa which are imbedded in the calcareous frameworkswe know as corals. And then in certain pelagic types, grouped as Siphonophora,the united individuals, in some cases alike, are in other cases severallytransformed in adaptation to various functions; so that the component individuals,assuming the characters of different organs, become practically combinedinto a single organism.

From this kind of integration we pass to a kind in which the individualsare not physically united but simply associated -- are integrated only bytheir mutual dependence. We may set down two kinds -- those which occur withinthe same species, and those which occur between members of different species.

More or less of the gregarious tendency is common among animals; and whenit is marked, there is, in addition to simple aggregation, some degree ofcombination. Creatures that hunt in packs, or that have sentinels, or thatare governed by leaders, form bodies partially united by co-operation. Amongpolygamous mammals and birds this mutual dependence is closer; and the socialinsects show us still more consolidated assemblages: some of them havingtheir members so united that they cannot live independently How organismsin their totality are mutually dependent, and in that sense integrated, weshall see on remembering -- first, that while all animals live directly orindirectly on plants, plants utilize the carbon dioxide excreted by animals;second, that among animals the flesh-eaters cannot exist without the plant-eaters;third, that a large proportion of plants can continue their respective racesonly by the help of insects. Without detailing the more complex connexions,which Mr. Darwin has so beautifully illustrated, it will suffice to say thatthe Flora and Fauna in each habitat, constitute an aggregate so far integratedthat many of its species die out if placed amid the plants and animals ofanother habitat. And this integration, too, increases as organic evolutionadvances. §111. The phenomena set down in the foregoing paragraph introduceus to others of a higher order, with which they ought, in strictness, tobe grouped-phenomena which we may term super-organic. Inorganic bodies presentus with certain facts. Additional facts, mostly of a more involved kind,are presented by organic bodies. There remain yet further facts, not presentedby any organic body taken singly, but which result from the actions of aggregatedorganic bodes. Though phenomena of this order are, as we see, foreshadowedamong inferior organisms, they become so conspicuous in mankind as sociallyunited, that practically we may consider them to commence here.

In the social organism integrative changes are abundantly exemplified.

Uncivilized societies display them when wandering families, such as thoseof Bushmen, join into tribes of considerable size. A further progress inmass results from the subjugation of weak tribes by strong ones; and in thesubordination of their respective chiefs to the conquering chief. Such combinationswhich, among aboriginal races, are continually being formed and continuallybroken up, become, among superior races, relatively permanent. If we tracethe stages through which our own society, or any adjacent one, has passed,we see this unification from time to time repeated on a larger scale andgaining in stability The consequent establishment of groups of vassals boundto their respective lords; the subsequent subjection of groups of inferiornobles to dukes or earls; and the still later growth of the kingly powerover dukes and earls; are so many instances of increasing consolidation.

This process slowly completes itself by destroying the original lines ofdemarcation. And of the European nations it may be further remarked, thatin the tendency to form alliances, in the restraining influences exercisedby governments over one another, in the system of settling internationalarrangements by congresses, as well as in the weakening of commercial barriersand the increasing facilities of communication, we see the beginnings ofa European federation -- a still larger integration that any now established.

But it is not only in these external unions of groups with groups, andof the compound groups with one another, that the general law is exemplified.