The relation of these two types, at least, to their zones of distribution is relatively easy to explain. Mediterranean man is highly susceptible to diseases of the breathing-organs to which the fair-haired Nordic type is more resistant. Here is one possible explanation of their command of their respective habitats, and there are many others. The forest-dwelling Nordic type, as Prof. Penck points out, must necessarily have had the family as the unit, for only by dwelling in small family groups can primitive man war against the forest. Mediterranean man, with his early use of irrigation, had necessarily to evolve a larger unit, for irrigation means extensive co-operation, so that political organisations would arise early in the Mediterranean. We can hardly doubt that these two facts had some bearing on the survival rate of the two races. The Nordic race with their strong family life, and with their abundant pasturage, had doubtless a relatively low death-rate among the children, though, as Prof. Myres points out, the struggle in adult life must have been keen. In the Mediterranean, as he also notes, the dry summer means difficulties with the water supply, difficulties in sanitation, and the risk of pestilence, which, with the abundant supply of fruit and the absence or scarcity of milk, has probably always meant a very high death-rate among the children. But the fact that the struggle for existence among adults was much less keen than among the forest folk, perhaps prevented this high infantile death-rate from being a great handicap. Once the geographical surroundings of the two peoples were changed by migration, the qualities which aided them to survive in their native habitat might become a positive hindrance. In brief, as two types evolved in harmony with well-defined geographical conditions, the very perfectness of their respective adaptations would hinder either from appropriating the territory of the other, while leaving a considerable margin for struggle on the debatable land between the two geographical regions.
If it seems at the present day that the Nordic race has more than passed the Mediterranean in the race of life, we must remember that the fact that coal is chiefly found in the territory of the former, has given it an enormous economic advantage in recent times, an advantage which it may not be able to keep.
The Alpine race presents a much more difficult problem. We have said nothing here of the so-called Aryan problem, because the whole conception of an Aryan race advancing from Asia with a ready-made culture, and imposing it upon a barbarian Europe, is somewhat out of date, and much that has been written on the subject of the Aryans preceded in time the disentanglement of the complex problems presented by European races. But with all deductions made, the incoming Asiatic race which we have called Alpine presents many curious problems. It seems probable that the languages of Europe are largely due to the grafting of Alpine or Eurasian tongues upon the different tongues already spoken by Mediterranean man. We have still in Britain a Celtic language, though it is spoken by people of Mediterranean characters, and it is an extraordinary fact that a people should impose its language and culture upon another race, and yet be itself unable to keep its footing among that race.
It has been suggested that the new-comers, in Britain at least, were never more than an aristocracy, and that they disappeared by the mingling of their blood with the indigenous people, after having long dominated them. That is, it was as if we might suppose that the British population in India was cut off from the mother country, and ultimately disappeared owing to intermarriage, while their language and their customs remained in greatly modified form and replaced the existing languages and customs.
The difficulties in regard to this hypothesis are twofold. In the first place, such a hypothesis of mingling seems inconsistent with the extraordinary persistency which this race has manifested in other parts of Europe, where it came into contact with the same races as in Britain; and, second, the position of the Alpine race in western Europe generally, its virtual limitation to relatively infertile land, seems inconsistent with the notion that it ever formed an aristocracy, apart from and above the other races. To-day in Germany it is so far from occupying the position of an aristocracy that it sometimes forms the lower classes to a Nordic dominant class, though the Alpine race is sometimes stated to be better adapted to town life than the Nordic.
Of the three races, Mediterranean man seems to be perfectly adapted to a dry region, with deficient pasture, naturally clothed with a drought-resisting type of forest. As he prospered he spread beyond his own region, with the result that he reached a region markedly different in climate and vegetation from his own, to which his adaptation was never very perfect. Where, as in Ireland and western Great Britain, the conditions permitted the natural growth of some of the Mediterranean plants, there his hold was fairly firm, elsewhere it must always have been loose and uncertain.
Into a Europe thus peopled, with probably large vacant spaces, came a pastoral type of man from Asia, certainly a transporter, if not an originator, of a higher culture, best fitted for a region of pasture land, but better fitted than Mediterranean man to withstand cold. He filled the spaces which Mediterranean man could not fill, and pressed him hard in many places. Ultimately the forest region of Europe evolved its own type, perhaps from some aberrant strain of Mediterranean man, and this type, perfectly fitted to the forest regions, conquered the north and west, driving Alpine man up to the hills, and largely displacing Mediterranean man except where distinctively Mediterranean influences prevailed.
To the east, as the European forest dies away into the steppes of Asia, Nordic man can no longer compete successfully with Alpine man, and diminishes in numbers and in strength.
Thus while in Germany the tendency is for the tall, fair longheads of the north to dominate the short, darker broadheads of the south, further to the east this same broad-headed race, under the banner of Panslavism, strives, not unsuccessfully, to dominate the longheads of Finland and elsewhere.
Thus below and beneath the warfare of race is the contrast of physical conditions, which have produced the various types of man, no less than of plants and animals, and from which man cannot fully emancipate himself.