skull:  the higher forms being distinguished by the relatively larger size of the bones which cover the brain, and the relatively smaller size of those which form the jaw, etc.  Now, this characteristic, which is stronger in Man than in any other creature, is stronger in the European than in the savage.  Moreover, judging from the greater extent and variety of faculty he exhibits, we may infer that the civilised man has also a more complex or heterogeneous nervous system than the uncivilised man:  and indeed the fact is in part visible in the increased ratio which his cerebrum bears to the subjacent ganglia.

If further elucidation be needed, we may find it in every nursery.  The infant European has sundry marked points of resemblance to the lower human races; as in the flatness of the alae of the nose, the depression of its bridge, the divergence and forward opening of the nostrils, the form of the lips, the absence of a frontal sinus, the width between the eyes, the smallness of the legs.  Now, as the development process by which these traits are turned into those of the adult European, is a continuation of that change from the homogeneous to the heterogeneous displayed during the previous evolution of the embryo, which every physiologist will admit; it follows that the parallel developmental process by which the like traits of the barbarous races have been turned into those of the civilised races, has also been a continuation of the change from the homogeneous to the heterogeneous.  The truth of the second position—­that Mankind, as a whole, have become more heterogeneous—­is so obvious as scarcely to need illustration.  Every work on Ethnology, by its divisions and subdivisions of races, bears testimony to it.  Even were we to admit the hypothesis that Mankind originated from several separate stocks, it would still remain true, that as, from each of these stocks, there have sprung many now widely different tribes, which are proved by philological evidence to have had a common origin, the race as a whole is far less homogeneous than it once was.  Add to which, that we have, in the Anglo-Americans, an example of a new variety arising within these few generations; and that, if we may trust to the description of observers, we are likely soon to have another such example in Australia.

On passing from Humanity under its individual form, to Humanity as socially embodied, we find the general law still more variously exemplified.  The change from the homogeneous to the heterogeneous is displayed equally in the progress of civilisation as a whole, and in the progress of every tribe or nation; and is still going on with increasing rapidity.  As we see in existing barbarous tribes, society in its first and lowest form is a homogeneous aggregation of individuals having like powers and like functions:  the only marked difference of function being that which accompanies difference of sex.  Every man is warrior, hunter, fisherman, tool-maker, builder;