and Samnites, preceded the first ascending stage of the Roman civilization. And our own country, peopled by different divisions of the Aryan race, and mainly by varieties of Scandinavians, again illustrates this effect produced by the mixture of units sufficiently alike to coöperate in the same social system, but sufficiently unlike to prevent that social system from becoming forthwith definite in structure.
Admitting that the evidence where so many causes are in operation cannot be satisfactorily disentangled, and claiming only probability for these inductions respecting social constitutions, it remains to point out their analogy to certain inductions respecting the constitutions of individual living things. Between organisms widely unlike in kind, no progeny can arise: the physiological units contributed by them respectively to form a fertilized germ cannot work together so as to produce a new organism. Evidently as, while multiplying, the two classes of units tend to build themselves into two different structures, their conflict prevents the formation of any structure. If the two organisms are less unlike in kind—belonging, say, to the same genus though to different species—the two structures which their two groups of physiological units tend to build up being tolerably similar, they can, and do, coöperate in making an organism that is intermediate. But this, though it will work, is imperfect in its latest-evolved parts: there results a mule incapable of propagating. If, instead of different species, remote varieties are united, the intermediate organism is not infertile; but many facts suggest the conclusion that infertility results in subsequent generations: the incongruous working of the united structures, though longer in showing itself, comes out ultimately. And then, finally, if, instead of remote varieties, varieties nearly allied are united, a permanently-fertile breed results; and, while the slight differences of the two kinds of physiological units are not such as to prevent harmonious coöperation, they are such as conduce to plasticity and unusually vigorous growth.
Here, then, seems a parallel to the conclusion indicated above, that hybrid societies are imperfectly organizable—cannot grow into forms completely stable; while societies that have been evolved from mixtures of nearly-allied varieties of man can assume stable structures, and have an advantageous modifiability.
We class societies, then, in two ways; both having to be kept in mind when interpreting social phenomena:
First, they have to be arranged in the order of their integration, as simple, compound, doubly-compound, trebly-compound. And, along with the increasing degrees of evolution implied by these ascending stages of composition, we have to recognize the increasing degrees of evolution implied by growing heterogeneity, general and local.
Much less definite is the division to be made among societies according as one or other of their great systems of organs is supreme.
